A control and test system of a landing gear drop test rig is developed considering the drop test specifica- tions for the ＂Seagull 300＂ multi-functional amphibious airplane. In order to realize the automation of dro...A control and test system of a landing gear drop test rig is developed considering the drop test specifica- tions for the ＂Seagull 300＂ multi-functional amphibious airplane. In order to realize the automation of drop test process, a servo system is proposed and programmable logic controller（PLC） technology is used. Several key technologies for measuring the horizontal load, the vertical load and the transient rotational speed are studied. According to the requirements of CCAR-23-R3, the drop test of landing gears of the ＂Seagull 300＂ airplane is accomplished. Test results show that the system has a high accuracy of data collection. The system is stable and reliable. The drop test satisfies the requirements of the drop test specifications and the results can be used as the certification of airworthiness for this kind of airplane.展开更多
[Objective] This study was conducted to optimize the suitable application amounts of nitrogen fertilizer and phosphate fertilizer for winter wheat.[Method] A field experiment was carried out to investigate the effects...[Objective] This study was conducted to optimize the suitable application amounts of nitrogen fertilizer and phosphate fertilizer for winter wheat.[Method] A field experiment was carried out to investigate the effects of the application amounts of nitrogen fertilizer and phosphate fertilizer on the yield of winter wheat.[Result]The quadratic simulation function between the application of nitrogen fertilizer and wheat yield was y =-0.6611x^2＋20.091 x ＋234.85,with a correlation coefficient of0.970 8,and the yield of winter wheat was the highest at the application amount of nitrogen fertilizer of 228.0 kg/hm^2.The quadratic simulation function between the application of phosphate fertilizer and wheat yield was y =-0.572 6x^2＋13.168 x ＋340.4,with a correlation coefficient of 0.921 95,and the yield of winter wheat was the highest at the application amount of phosphate fertilizer of 172.5 kg/hm^2.[Conclusion] This study provides a scientific basis for the rational application of nitrogen fertilizer and phosphate fertilizer on winter wheat.展开更多
This paper addresses the development and testing of a remotely controlled boat platform with an innovative air-ventilated hull. The application of air cavities on the underside of ship hulls is a promising means for r...This paper addresses the development and testing of a remotely controlled boat platform with an innovative air-ventilated hull. The application of air cavities on the underside of ship hulls is a promising means for reducing hydrodynamic drag and pollutant emissions and increasing marine transportation efficiency. Despite this concept＇s potential, design optimization and high-performance operation of novel air-cavity ships remain a challenging problem. Hull construction and sensor instrumentation of the model-scale air-cavity boat is described in the paper. The modular structure of the hull allows for easy modifications, and an electric propulsion unit enables self-propelled operation. The boat is controlled remotely via a radio transmission system. Results of initial tests are reported, including thrust, speed, and airflow rate in several loading conditions. The constructed platform can be used for optimizing air-cavity systems and testing other innovative hull designs. This system can be also developed into a high-performance unmanned boat.展开更多
Components of mechanical product are assembled by structural joints,such as bolting,riveting,welding,etc.Structural joints introduce nonlinearity to some engineering structures,and the nonlinearity need to be modeled ...Components of mechanical product are assembled by structural joints,such as bolting,riveting,welding,etc.Structural joints introduce nonlinearity to some engineering structures,and the nonlinearity need to be modeled precisely.To meet serious quality requirements,it is necessary to detect and identify nonlinearity of mechanical products for structural optimization.Modal test to acquire a dynamic response has been applied for decades,which provides reliable results for finite element(FE)model updating.Here response control vibration test for identification of nonlinearity is presented.A nonlinear system can be regarded as linearity for particular steady state response,and classical linear analysis tool is applicable to extract modal data for particular response.First,its applicability is illustrated by some numerical simulations.Subsequently,it is implemented on experimental setup with structural joints by shaking table.The stiffness and damping function dependent of relative displacement are fitted to describe its inherent nonlinearity.The spring and damping forces are identified by harmonic balance method(HBM)to predict output response.Based on the identified results,the procedure is recommended that it allows a reliable measurement of nonlinearity with a certain accuracy.展开更多
Both auto-power spectrum and cross-power spectrum need to be controlled in multi-input multi-output （MIMO） random vibration test. During the control process with the difference control algorithm （DCA）, a lower tri...Both auto-power spectrum and cross-power spectrum need to be controlled in multi-input multi-output （MIMO） random vibration test. During the control process with the difference control algorithm （DCA）, a lower triangular matrix is derived from Cholesky decomposition of a reference spectrum matrix. The diagonal elements of the lower triangular matrix （DELTM） may become negative. These negative values have no meaning in physical significance and can cause divergence of auto-power spectrum control. A proportional root mean square control algorithm （PRMSCA） provides another method to avoid the divergence caused by negative values of DELTM, but PRMSCA cannot control the cross-power spectrum. A new control algorithm named matrix power control algorithm （MPCA） is proposed in the paper. MPCA can guarantee that DELTM is always positive in the auto-power spectrum control. MPCA can also control the cross-power spectrum. After these three control algorithms are analyzed, three-input three-output random vibration control tests are implemented on a three-axis vibration shaker. The results show the validity of the proposed MPCA.展开更多
BACKGROUND Childhood asthma is a common respiratory ailment that significantly affects preschool children.Effective asthma management in this population is particularly challenging due to limited communication skills ...BACKGROUND Childhood asthma is a common respiratory ailment that significantly affects preschool children.Effective asthma management in this population is particularly challenging due to limited communication skills in children and the necessity for consistent involvement of a caregiver.With the rise of digital healthcare and the need for innovative interventions,Internet-based models can potentially offer relatively more efficient and patient-tailored care,especially in children.AIM To explore the impact of an intelligent Internet care model based on the child respiratory and asthma control test(TRACK)on asthma management in preschool children.METHODS The study group comprised preschoolers,aged 5 years or younger,that visited the hospital's pediatric outpatient and emergency departments between January 2021 and January 2022.Total of 200 children were evenly and randomly divided into the observation and control groups.The control group received standard treatment in accordance with the 2016 Guidelines for Pediatric Bronchial Asthma and the Global Initiative on Asthma.In addition to above treatment,the observation group was introduced to an intelligent internet nursing model,emphasizing the TRACK scale.Key measures monitored over a six-month period included the frequency of asthma attack,emergency visits,pulmonary function parameters(FEV1,FEV1/FVC,and PEF),monthly TRACK scores,and the SF-12 quality of life assessment.Post-intervention asthma control rates were assessed at six-month follow-up.RESULTS The observation group had fewer asthma attacks and emergency room visits than the control group(P<0.05).After six months of treatment,the children in both groups had higher FEV1,FEV1/FVC,and PEF(P<0.05).Statistically significant differences were observed between the two groups(P<0.05).For six months,children in the observation group had a higher monthly TRACK score than those in the control group(P<0.05).The PCS and MCSSF-12 quality of life scores were relatively higher than those before the nursing period(P<0.05).Furthermore,the groups showed statistically significant differences(P<0.05).The asthma control rate was higher in the observation group than in the control group(P<0.05).CONCLUSION TRACK based Intelligent Internet nursing model may reduce asthma attacks and emergency visits in asthmatic children,improve lung function,quality of life,and the TRACK score and asthma control rate.The effect of nursing was significant,allowing for development of an asthma management model.展开更多
This paper employs a velocity plus displacement（V＋D）-based equivalent force control（EFC） method to solve the velocity/displacement difference equation in a real-time substructure test. This method uses type 2 fee...This paper employs a velocity plus displacement（V＋D）-based equivalent force control（EFC） method to solve the velocity/displacement difference equation in a real-time substructure test. This method uses type 2 feedback control loops to replace mathematical iteration to solve the nonlinear dynamic equation. A spectral radius analysis of the amplification matrix shows that the type 2 EFC-explicit, Newmark-β method has beneficial numerical characteristics for this method. Its stability limit of Ω = 2 remains unchanged regardless of the system damping because the velocity is achieved with very high accuracy during simulation. In contrast, the stability limits of the central difference method using direct velocity prediction and the EFC-average acceleration method with linear interpolation are shown to decrease with an increase in system damping. In fact, the EFC-average acceleration method is shown to change from unconditionally stable to conditionally stable. We also show that if an over-damped system with a damping ratio of 1.05 is considered, the stability limit is reduced to Ω =1.45. Finally, the results from an experiment with a single-degree-of-freedom structure installed with a magneto-rheological（MR） damper are presented. The results demonstrate that the proposed method is able to follow both displacement and velocity commands with moderate accuracy, resulting in improved test performance and accuracy for structures that are sensitive to both velocity and displacement inputs. Although the findings of the study are promising, additional test data and several further improvements will be required to draw general conclusions.展开更多
Laser heating technology is a type of potential and attractive space heat flux simulation technology, which is characterized by high heating rate, controlled spatial intensity distribution and rapid response. However,...Laser heating technology is a type of potential and attractive space heat flux simulation technology, which is characterized by high heating rate, controlled spatial intensity distribution and rapid response. However, the controlled plant is nonlinear, time-varying and uncertainty when implementing the laser-based heat flux simulation. In this paper, a novel intelligent adaptive controller based on proportion-integration-differentiation (PID) type fuzzy logic is proposed to improve the performance of laser-based ground thermal test. The temperature range of thermal cycles is more than 200 K in many instances. In order to improve the adaptability of controller, output scaling factors are real time adjusted while the thermal test is underway. The initial values of scaling factors are optimized using a stochastic hybrid particle swarm optimization (H-PSO) algorithm. A validating system has been established in the laboratory. The performance of the proposed controller is evaluated through extensive experiments under different operating conditions (reference and load disturbance). The results show that the proposed adaptive controller performs remarkably better compared to the conventional PID (PID) controller and the conventional PID type fuzzy (F-PID) controller considering performance indicators of overshoot, settling time and steady state error for laser-based ground thermal test. It is a reliable tool for effective temperature control of laser-based ground thermal test. (C) 2016 Chinese Society of Aeronautics and Astronautics. Production and hosting by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.展开更多
Setting: Three pediatric pneumatologist offices in Bucaramanga, Colombia. Objective: To establish the concordance between medical criteria and the Childhood-Asthma Control Test (cACT). Design: Study of the assessment ...Setting: Three pediatric pneumatologist offices in Bucaramanga, Colombia. Objective: To establish the concordance between medical criteria and the Childhood-Asthma Control Test (cACT). Design: Study of the assessment of diagnostic technology using transverse sampling. 127 asthma patients aged between 4 and 11 years and their parents filled before clinical evaluation made by a pediatric pneumologist. Patients were classified as controlled or not controlled. Criteria validity was established comparing this classification using Cohen’s kappa and performance indicators according to ROC analysis. Results: 78% of the patients were controlled;patients who are not controlled have a higher score in cACT (mean difference: 3.25 points). Concordance among cACT subscales is acceptable (ρ = 0.554). cACT’s sensitivity was 53.6%, specificity 78.8%, positive likelihood ratio (LR+) 2.53, and negative likelihood ratio (LR-) 0.59. The best cut-off point is 15, with 98% sensitivity, a specificity of 14.3%, LR+ in 1.14, and LR- in 0.14. Conclusions: cACT is a valid tool to determine asthma control in children without replacing medical criteria or other clinical tests. In populations with difficult access to high complexity services, it is useful to decide whether urgent referral to the specialist is necessary.展开更多
A wind turbine system equipped with a tuned liquid column damper （TLCD） is comprehensively studied via shaking table tests using a 1/13-scaled model. The effects of wind and wave actions are considered by inputting ...A wind turbine system equipped with a tuned liquid column damper （TLCD） is comprehensively studied via shaking table tests using a 1/13-scaled model. The effects of wind and wave actions are considered by inputting response- equivalent accelerations on the shaking table. The test results show that the control effect of the TLCD system is significant in reducing the responses under both wind-wave equivalent loads and ground motions, but obviously varies for different inputs, Further, a blade-hub-tower integrated numerical model for the wind turbine system is established. The model is capable of considering the rotational effect of blades by combining Kane＇s equation with the finite element method. The responses of the wind tower equipped with TLCD devices are numerically obtained and compared to the test results, showing that under both controlled and uncontrolled conditions with and without blades＇ rotation, the corresponding responses exhibit good agreement. This demonstrates that the proposed numerical model performs well in capturing the wind-wave coupled response of the offshore wind turbine systems under control. Both numerical and experimental results show that the TLCD system can significantly reduce the structural response and thus improve the safety and serviceability of the offshore wind turbine tower systems. Additional issues that require further study are discussed.展开更多
A high fidelity dynamic model of a high-energy hydraulically-actuated shock test machine for heavy weight devices is presented to satisfy the newly-built shock resistance standard and simulate the actual underwater ex...A high fidelity dynamic model of a high-energy hydraulically-actuated shock test machine for heavy weight devices is presented to satisfy the newly-built shock resistance standard and simulate the actual underwater explosion environments in laboratory as well as increase the testing capability of shock test machine. In order to produce the required negative shock pulse in the given time duration, four hydraulic actuators are utilized. The model is then used to formulate an advanced feedforward controller for the system to produce the required negative waveform and to address the motion synchronization of the four cylinders. The model provides a safe and easily controllable way to perform a ＂virtual testing＂ before starting potentially destructive tests on specimen and to predict performance of the system. Simulation results have demonstrated the effectiveness of the controller.展开更多
Cattle from 20 dairy farms were serologically tested over a five-year period using agar gel immunodiffusion test (AGIDT) as part of a voluntary Bovine Leukemia Virus (BLV) control program. After five years of removing...Cattle from 20 dairy farms were serologically tested over a five-year period using agar gel immunodiffusion test (AGIDT) as part of a voluntary Bovine Leukemia Virus (BLV) control program. After five years of removing infected animals from the herds based on BLV-AGIDT serological status, blood samples from 332 cattle in these farms were collected and analyzed side by side by AGIDT and enzyme-linked immunosorbent assay (ELISA) to detect antibodies against BLV. AGIDT detected 29.2% (97) and 16.0% (53) of the animals as positive and weak positive respectively, whereas ELISA detected 58.2% (193) cattle as positive. The prevalence of BLV-antibodies determined with AGIDT in the dairy farms oscillated between 0% and 86%, whereas prevalence determined by ELISA ranged between 28% and 100% in the same farms. Although both techniques showed similarly results in farms with high BLV-prevalence, ELISA detected a larger proportion of BLV-positive, especially in farms with low or no BLV-prevalence based on AGIDT, leading to wrong assumptions in terms of farm level control efforts. Our results strongly suggest that AGIDT alone is inadequate to implement BLV control programs and ELISA is a more adequate test for BLV surveillance and control programs.展开更多
Due to the high difficulties, high investment, and high risks in deepwater oil and gas well testing, major safety problems can occur easily. A key to prevent accidents is to conduct safety assessment and control on de...Due to the high difficulties, high investment, and high risks in deepwater oil and gas well testing, major safety problems can occur easily. A key to prevent accidents is to conduct safety assessment and control on deepwater testing and to improve the testing technology. The deepwater of the South China Sea has some special environmental features: long distance from offshore, frequent typhoons in summer and constant monsoons in winter, and the presence of sandy slopes, sandy ridges and internal waves, coupled with the complex properties of oil and gas reserves which bring more challenges to deepwater well testing. In combination with deepwater well testing practice in the South China Sea, this paper analyzes the main potential risks in deepwater well testing and concludes that there are risks of failures of testing string, tools, and ground processes. Other risks are gas hydrate blockage, reservoir stratum sanding, and typhoon impacts. Specific precautions are also proposed in response to these risks in the paper.展开更多
The temperature-Altitude Test System(TATS) supplies various testing environments.The traditional PID method controls the temperature in TATS Temperature-Pressure Cabin(TPC) over a long adjusting time and with a large ...The temperature-Altitude Test System(TATS) supplies various testing environments.The traditional PID method controls the temperature in TATS Temperature-Pressure Cabin(TPC) over a long adjusting time and with a large overshoot.In order to solve this problem simply,a temperature control strategy with temperature difference corresponding factors is presented through a dynamic analysis and modeling of TPC temperature change.The TPC temperature descending process is simulated,and the results show that this control strategy can allot the proportion of PID heating controller and PID cooling controller in the whole control process and TPC temperature can be controlled at a set point quickly and effectively.展开更多
This paper presents a method of NTP-based time synchronization and a strategy of master-slave server structured time synchronization to ensure the test and control system of aeroengine to be time-synchronized. Based o...This paper presents a method of NTP-based time synchronization and a strategy of master-slave server structured time synchronization to ensure the test and control system of aeroengine to be time-synchronized. Based on time synchronization, the hierarchy and the integration of the measurement and control system of aeroengine are investigated. In result, our method is successfully applied for multiple front-end tests in a simulative altitude test facility of aeroengine.展开更多
The synthetic making test has been widely used in evaluating the break ability of high-voltage circuit breaker. However, the test research and application are still inadequate, especially in the condition of rated vol...The synthetic making test has been widely used in evaluating the break ability of high-voltage circuit breaker. However, the test research and application are still inadequate, especially in the condition of rated voltage. According to the realistic conditions of test stations in China, a control device based on pre-arcing current detection and phase control is proposed in this paper. A sample of the control device made up of DSP TMS320LF2407A is fabricated, in which the CPLD MAX7064 is used to transmit signals for EMC design. It can be applied in full voltage synthetic making test at a level of 126kV/63kA. The test results show that, it is accurate to control the making phase of the applied voltage, whether the closing is demanded at voltage peak or zero.展开更多
this paper describes the design of a feedback testing system for locomtive tractionmotor. The structures and features of the software and hardware of themicrocomputer control system have been studied. This testing sys...this paper describes the design of a feedback testing system for locomtive tractionmotor. The structures and features of the software and hardware of themicrocomputer control system have been studied. This testing system hasalready been put into operation successfully in several locomotive depots inChina.展开更多
Software has been developed for digital control of WDW series testing machine and the measurement of fracture toughness by modularized design. Development of the software makes use of multi-thread and serial communica...Software has been developed for digital control of WDW series testing machine and the measurement of fracture toughness by modularized design. Development of the software makes use of multi-thread and serial communication techniques, which can accurately control the testing machine and measure the fracture toughness in real-time. Three-point bending specimens were used in the measurement. The software operates stably and reliably, expanding the function of WDW series testing machine.展开更多
The coagulation laboratory aids the clinician in as- sessing not only the bleeding patient but also the throm- botic patient.The techniques of coagulation laboratory are used to evaluate not only the coagulation syste...The coagulation laboratory aids the clinician in as- sessing not only the bleeding patient but also the throm- botic patient.The techniques of coagulation laboratory are used to evaluate not only the coagulation system but also the anti-coagulation system,fibrinolytic system, platelet and vascular endothelial function.Enzymes,in- hibitors,plasma factors and co-factors,cellular release products,and cell receptors can be measured in coagula- tion laboratory.It is most important for guaranteeing the diagnostic value of coagulation tests that quality control and assurance in the coagulation laboratory is ensured.展开更多
基金Supported by the Aviation Science Foundation of China(2009ZA52001)the Research Foundation(20070287033)~~
文摘A control and test system of a landing gear drop test rig is developed considering the drop test specifica- tions for the ＂Seagull 300＂ multi-functional amphibious airplane. In order to realize the automation of drop test process, a servo system is proposed and programmable logic controller（PLC） technology is used. Several key technologies for measuring the horizontal load, the vertical load and the transient rotational speed are studied. According to the requirements of CCAR-23-R3, the drop test of landing gears of the ＂Seagull 300＂ airplane is accomplished. Test results show that the system has a high accuracy of data collection. The system is stable and reliable. The drop test satisfies the requirements of the drop test specifications and the results can be used as the certification of airworthiness for this kind of airplane.
文摘[Objective] This study was conducted to optimize the suitable application amounts of nitrogen fertilizer and phosphate fertilizer for winter wheat.[Method] A field experiment was carried out to investigate the effects of the application amounts of nitrogen fertilizer and phosphate fertilizer on the yield of winter wheat.[Result]The quadratic simulation function between the application of nitrogen fertilizer and wheat yield was y =-0.6611x^2＋20.091 x ＋234.85,with a correlation coefficient of0.970 8,and the yield of winter wheat was the highest at the application amount of nitrogen fertilizer of 228.0 kg/hm^2.The quadratic simulation function between the application of phosphate fertilizer and wheat yield was y =-0.572 6x^2＋13.168 x ＋340.4,with a correlation coefficient of 0.921 95,and the yield of winter wheat was the highest at the application amount of phosphate fertilizer of 172.5 kg/hm^2.[Conclusion] This study provides a scientific basis for the rational application of nitrogen fertilizer and phosphate fertilizer on winter wheat.
基金Foundation item： Supported by the National Science Foundation （CMMI-1026264 and EEC-1157094）.
文摘This paper addresses the development and testing of a remotely controlled boat platform with an innovative air-ventilated hull. The application of air cavities on the underside of ship hulls is a promising means for reducing hydrodynamic drag and pollutant emissions and increasing marine transportation efficiency. Despite this concept＇s potential, design optimization and high-performance operation of novel air-cavity ships remain a challenging problem. Hull construction and sensor instrumentation of the model-scale air-cavity boat is described in the paper. The modular structure of the hull allows for easy modifications, and an electric propulsion unit enables self-propelled operation. The boat is controlled remotely via a radio transmission system. Results of initial tests are reported, including thrust, speed, and airflow rate in several loading conditions. The constructed platform can be used for optimizing air-cavity systems and testing other innovative hull designs. This system can be also developed into a high-performance unmanned boat.
文摘Components of mechanical product are assembled by structural joints,such as bolting,riveting,welding,etc.Structural joints introduce nonlinearity to some engineering structures,and the nonlinearity need to be modeled precisely.To meet serious quality requirements,it is necessary to detect and identify nonlinearity of mechanical products for structural optimization.Modal test to acquire a dynamic response has been applied for decades,which provides reliable results for finite element(FE)model updating.Here response control vibration test for identification of nonlinearity is presented.A nonlinear system can be regarded as linearity for particular steady state response,and classical linear analysis tool is applicable to extract modal data for particular response.First,its applicability is illustrated by some numerical simulations.Subsequently,it is implemented on experimental setup with structural joints by shaking table.The stiffness and damping function dependent of relative displacement are fitted to describe its inherent nonlinearity.The spring and damping forces are identified by harmonic balance method(HBM)to predict output response.Based on the identified results,the procedure is recommended that it allows a reliable measurement of nonlinearity with a certain accuracy.
基金National Natural Science Foundation of China （10972104） The Fundamental Research Funds for NUAA（NS2010007）
文摘Both auto-power spectrum and cross-power spectrum need to be controlled in multi-input multi-output （MIMO） random vibration test. During the control process with the difference control algorithm （DCA）, a lower triangular matrix is derived from Cholesky decomposition of a reference spectrum matrix. The diagonal elements of the lower triangular matrix （DELTM） may become negative. These negative values have no meaning in physical significance and can cause divergence of auto-power spectrum control. A proportional root mean square control algorithm （PRMSCA） provides another method to avoid the divergence caused by negative values of DELTM, but PRMSCA cannot control the cross-power spectrum. A new control algorithm named matrix power control algorithm （MPCA） is proposed in the paper. MPCA can guarantee that DELTM is always positive in the auto-power spectrum control. MPCA can also control the cross-power spectrum. After these three control algorithms are analyzed, three-input three-output random vibration control tests are implemented on a three-axis vibration shaker. The results show the validity of the proposed MPCA.
基金Supported by Science and Technology Research Project of Songjiang District,No.2020SJ340.
文摘BACKGROUND Childhood asthma is a common respiratory ailment that significantly affects preschool children.Effective asthma management in this population is particularly challenging due to limited communication skills in children and the necessity for consistent involvement of a caregiver.With the rise of digital healthcare and the need for innovative interventions,Internet-based models can potentially offer relatively more efficient and patient-tailored care,especially in children.AIM To explore the impact of an intelligent Internet care model based on the child respiratory and asthma control test(TRACK)on asthma management in preschool children.METHODS The study group comprised preschoolers,aged 5 years or younger,that visited the hospital's pediatric outpatient and emergency departments between January 2021 and January 2022.Total of 200 children were evenly and randomly divided into the observation and control groups.The control group received standard treatment in accordance with the 2016 Guidelines for Pediatric Bronchial Asthma and the Global Initiative on Asthma.In addition to above treatment,the observation group was introduced to an intelligent internet nursing model,emphasizing the TRACK scale.Key measures monitored over a six-month period included the frequency of asthma attack,emergency visits,pulmonary function parameters(FEV1,FEV1/FVC,and PEF),monthly TRACK scores,and the SF-12 quality of life assessment.Post-intervention asthma control rates were assessed at six-month follow-up.RESULTS The observation group had fewer asthma attacks and emergency room visits than the control group(P<0.05).After six months of treatment,the children in both groups had higher FEV1,FEV1/FVC,and PEF(P<0.05).Statistically significant differences were observed between the two groups(P<0.05).For six months,children in the observation group had a higher monthly TRACK score than those in the control group(P<0.05).The PCS and MCSSF-12 quality of life scores were relatively higher than those before the nursing period(P<0.05).Furthermore,the groups showed statistically significant differences(P<0.05).The asthma control rate was higher in the observation group than in the control group(P<0.05).CONCLUSION TRACK based Intelligent Internet nursing model may reduce asthma attacks and emergency visits in asthmatic children,improve lung function,quality of life,and the TRACK score and asthma control rate.The effect of nursing was significant,allowing for development of an asthma management model.
基金Scientific Research Fund of the Institute of Engineering Mechanics,CEA under Grant No.2016B09,2017A02 and 2016A06the National Natural Science Foundation of China under Grant No,51378478,51408565,51678538 and 51161120360the National ScienceTechnology Support Plan Projects(2016YFC0701106)
文摘This paper employs a velocity plus displacement（V＋D）-based equivalent force control（EFC） method to solve the velocity/displacement difference equation in a real-time substructure test. This method uses type 2 feedback control loops to replace mathematical iteration to solve the nonlinear dynamic equation. A spectral radius analysis of the amplification matrix shows that the type 2 EFC-explicit, Newmark-β method has beneficial numerical characteristics for this method. Its stability limit of Ω = 2 remains unchanged regardless of the system damping because the velocity is achieved with very high accuracy during simulation. In contrast, the stability limits of the central difference method using direct velocity prediction and the EFC-average acceleration method with linear interpolation are shown to decrease with an increase in system damping. In fact, the EFC-average acceleration method is shown to change from unconditionally stable to conditionally stable. We also show that if an over-damped system with a damping ratio of 1.05 is considered, the stability limit is reduced to Ω =1.45. Finally, the results from an experiment with a single-degree-of-freedom structure installed with a magneto-rheological（MR） damper are presented. The results demonstrate that the proposed method is able to follow both displacement and velocity commands with moderate accuracy, resulting in improved test performance and accuracy for structures that are sensitive to both velocity and displacement inputs. Although the findings of the study are promising, additional test data and several further improvements will be required to draw general conclusions.
文摘Laser heating technology is a type of potential and attractive space heat flux simulation technology, which is characterized by high heating rate, controlled spatial intensity distribution and rapid response. However, the controlled plant is nonlinear, time-varying and uncertainty when implementing the laser-based heat flux simulation. In this paper, a novel intelligent adaptive controller based on proportion-integration-differentiation (PID) type fuzzy logic is proposed to improve the performance of laser-based ground thermal test. The temperature range of thermal cycles is more than 200 K in many instances. In order to improve the adaptability of controller, output scaling factors are real time adjusted while the thermal test is underway. The initial values of scaling factors are optimized using a stochastic hybrid particle swarm optimization (H-PSO) algorithm. A validating system has been established in the laboratory. The performance of the proposed controller is evaluated through extensive experiments under different operating conditions (reference and load disturbance). The results show that the proposed adaptive controller performs remarkably better compared to the conventional PID (PID) controller and the conventional PID type fuzzy (F-PID) controller considering performance indicators of overshoot, settling time and steady state error for laser-based ground thermal test. It is a reliable tool for effective temperature control of laser-based ground thermal test. (C) 2016 Chinese Society of Aeronautics and Astronautics. Production and hosting by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.
文摘Setting: Three pediatric pneumatologist offices in Bucaramanga, Colombia. Objective: To establish the concordance between medical criteria and the Childhood-Asthma Control Test (cACT). Design: Study of the assessment of diagnostic technology using transverse sampling. 127 asthma patients aged between 4 and 11 years and their parents filled before clinical evaluation made by a pediatric pneumologist. Patients were classified as controlled or not controlled. Criteria validity was established comparing this classification using Cohen’s kappa and performance indicators according to ROC analysis. Results: 78% of the patients were controlled;patients who are not controlled have a higher score in cACT (mean difference: 3.25 points). Concordance among cACT subscales is acceptable (ρ = 0.554). cACT’s sensitivity was 53.6%, specificity 78.8%, positive likelihood ratio (LR+) 2.53, and negative likelihood ratio (LR-) 0.59. The best cut-off point is 15, with 98% sensitivity, a specificity of 14.3%, LR+ in 1.14, and LR- in 0.14. Conclusions: cACT is a valid tool to determine asthma control in children without replacing medical criteria or other clinical tests. In populations with difficult access to high complexity services, it is useful to decide whether urgent referral to the specialist is necessary.
基金National Natural Science Foundation of China Under Grant No.11172210National Hi-Tech Development Plan(863 Plan)Under Grant No.2008AA05Z413+2 种基金the Fundamental Fund for Central Universitiesthe Shuguang Program of Shanghai Citythe State Key Laboratory of Disaster Reduction in Civil Engineering Under Grant Nos.SLDRCE14-A-06 and SLDRCE14-B-17
文摘A wind turbine system equipped with a tuned liquid column damper （TLCD） is comprehensively studied via shaking table tests using a 1/13-scaled model. The effects of wind and wave actions are considered by inputting response- equivalent accelerations on the shaking table. The test results show that the control effect of the TLCD system is significant in reducing the responses under both wind-wave equivalent loads and ground motions, but obviously varies for different inputs, Further, a blade-hub-tower integrated numerical model for the wind turbine system is established. The model is capable of considering the rotational effect of blades by combining Kane＇s equation with the finite element method. The responses of the wind tower equipped with TLCD devices are numerically obtained and compared to the test results, showing that under both controlled and uncontrolled conditions with and without blades＇ rotation, the corresponding responses exhibit good agreement. This demonstrates that the proposed numerical model performs well in capturing the wind-wave coupled response of the offshore wind turbine systems under control. Both numerical and experimental results show that the TLCD system can significantly reduce the structural response and thus improve the safety and serviceability of the offshore wind turbine tower systems. Additional issues that require further study are discussed.
文摘A high fidelity dynamic model of a high-energy hydraulically-actuated shock test machine for heavy weight devices is presented to satisfy the newly-built shock resistance standard and simulate the actual underwater explosion environments in laboratory as well as increase the testing capability of shock test machine. In order to produce the required negative shock pulse in the given time duration, four hydraulic actuators are utilized. The model is then used to formulate an advanced feedforward controller for the system to produce the required negative waveform and to address the motion synchronization of the four cylinders. The model provides a safe and easily controllable way to perform a ＂virtual testing＂ before starting potentially destructive tests on specimen and to predict performance of the system. Simulation results have demonstrated the effectiveness of the controller.
文摘Cattle from 20 dairy farms were serologically tested over a five-year period using agar gel immunodiffusion test (AGIDT) as part of a voluntary Bovine Leukemia Virus (BLV) control program. After five years of removing infected animals from the herds based on BLV-AGIDT serological status, blood samples from 332 cattle in these farms were collected and analyzed side by side by AGIDT and enzyme-linked immunosorbent assay (ELISA) to detect antibodies against BLV. AGIDT detected 29.2% (97) and 16.0% (53) of the animals as positive and weak positive respectively, whereas ELISA detected 58.2% (193) cattle as positive. The prevalence of BLV-antibodies determined with AGIDT in the dairy farms oscillated between 0% and 86%, whereas prevalence determined by ELISA ranged between 28% and 100% in the same farms. Although both techniques showed similarly results in farms with high BLV-prevalence, ELISA detected a larger proportion of BLV-positive, especially in farms with low or no BLV-prevalence based on AGIDT, leading to wrong assumptions in terms of farm level control efforts. Our results strongly suggest that AGIDT alone is inadequate to implement BLV control programs and ELISA is a more adequate test for BLV surveillance and control programs.
文摘Due to the high difficulties, high investment, and high risks in deepwater oil and gas well testing, major safety problems can occur easily. A key to prevent accidents is to conduct safety assessment and control on deepwater testing and to improve the testing technology. The deepwater of the South China Sea has some special environmental features: long distance from offshore, frequent typhoons in summer and constant monsoons in winter, and the presence of sandy slopes, sandy ridges and internal waves, coupled with the complex properties of oil and gas reserves which bring more challenges to deepwater well testing. In combination with deepwater well testing practice in the South China Sea, this paper analyzes the main potential risks in deepwater well testing and concludes that there are risks of failures of testing string, tools, and ground processes. Other risks are gas hydrate blockage, reservoir stratum sanding, and typhoon impacts. Specific precautions are also proposed in response to these risks in the paper.
文摘The temperature-Altitude Test System(TATS) supplies various testing environments.The traditional PID method controls the temperature in TATS Temperature-Pressure Cabin(TPC) over a long adjusting time and with a large overshoot.In order to solve this problem simply,a temperature control strategy with temperature difference corresponding factors is presented through a dynamic analysis and modeling of TPC temperature change.The TPC temperature descending process is simulated,and the results show that this control strategy can allot the proportion of PID heating controller and PID cooling controller in the whole control process and TPC temperature can be controlled at a set point quickly and effectively.
文摘This paper presents a method of NTP-based time synchronization and a strategy of master-slave server structured time synchronization to ensure the test and control system of aeroengine to be time-synchronized. Based on time synchronization, the hierarchy and the integration of the measurement and control system of aeroengine are investigated. In result, our method is successfully applied for multiple front-end tests in a simulative altitude test facility of aeroengine.
文摘The synthetic making test has been widely used in evaluating the break ability of high-voltage circuit breaker. However, the test research and application are still inadequate, especially in the condition of rated voltage. According to the realistic conditions of test stations in China, a control device based on pre-arcing current detection and phase control is proposed in this paper. A sample of the control device made up of DSP TMS320LF2407A is fabricated, in which the CPLD MAX7064 is used to transmit signals for EMC design. It can be applied in full voltage synthetic making test at a level of 126kV/63kA. The test results show that, it is accurate to control the making phase of the applied voltage, whether the closing is demanded at voltage peak or zero.
文摘this paper describes the design of a feedback testing system for locomtive tractionmotor. The structures and features of the software and hardware of themicrocomputer control system have been studied. This testing system hasalready been put into operation successfully in several locomotive depots inChina.
文摘Software has been developed for digital control of WDW series testing machine and the measurement of fracture toughness by modularized design. Development of the software makes use of multi-thread and serial communication techniques, which can accurately control the testing machine and measure the fracture toughness in real-time. Three-point bending specimens were used in the measurement. The software operates stably and reliably, expanding the function of WDW series testing machine.
文摘The coagulation laboratory aids the clinician in as- sessing not only the bleeding patient but also the throm- botic patient.The techniques of coagulation laboratory are used to evaluate not only the coagulation system but also the anti-coagulation system,fibrinolytic system, platelet and vascular endothelial function.Enzymes,in- hibitors,plasma factors and co-factors,cellular release products,and cell receptors can be measured in coagula- tion laboratory.It is most important for guaranteeing the diagnostic value of coagulation tests that quality control and assurance in the coagulation laboratory is ensured.
