In order to quantitatively study the seismic absorption effect of the cushion on a superstructure, a numerical simulation and parametric study are carried out on the overall FEA model of a rigid-pile composite foundat...In order to quantitatively study the seismic absorption effect of the cushion on a superstructure, a numerical simulation and parametric study are carried out on the overall FEA model of a rigid-pile composite foundation in ABAQUS. A simulation of a shaking table test on a rigid mass block is first completed with ABAQUS and EERA, and the effectiveness of the Drucker-Prager constitutive model and the finite-infinite element coupling method is proved. Dynamic time-history analysis of the overall model under frequent and rare earthquakes is carried out using seismic waves from the El Centro, Kobe, and Bonds earthquakes. The different responses of rigid-pile composite foundations and pile-raft foundations are discussed. Furthermore, the influence of thickness and modulus of cushion, and ground acceleration on the seismic absorption effect of the cushion are analyzed. The results show that： 1） the seismic absorption effect of a cushion is good under rare earthquakes, with an absorption ratio of about 0.85; and 2） the seismic absorption effect is strongly affected by cushion thickness and ground acceleration.展开更多
TWINDELIVERIES The Commercial Aircraft Corp.of China Ltd.(COMAC)delivers two C919 planes,China's first domestically produced large passenger aircraft,to Air China and China Southern Airlines at COMAC's manufac...TWINDELIVERIES The Commercial Aircraft Corp.of China Ltd.(COMAC)delivers two C919 planes,China's first domestically produced large passenger aircraft,to Air China and China Southern Airlines at COMAC's manufacturing center in Shanghai on August 28.This was the first time these two airlines received the C919.To date,the COMAC has delivered nine C919 aircraft,seven of which went to China Eastern Airlines.Since the first C919 plane completed its maiden commercial flight in May 2023,the C919 fleet has successfully completed more than 3,000 flights,facilitating over 400,000 passenger trips.展开更多
HIGH LIGHT!The High Energy Photon Source(HEPS)under construction in Beijing on August 18.The project is expected to be ready for operation by the end of 2025.Once completed,the HEPS will be able to emit light that is ...HIGH LIGHT!The High Energy Photon Source(HEPS)under construction in Beijing on August 18.The project is expected to be ready for operation by the end of 2025.Once completed,the HEPS will be able to emit light that is 1 trillion times brighter than the sun,and will be open to users in fields such as aerospace,energy,environment,life science and pharmaceuticals.展开更多
The IndyCar series distinguishes itself by providing the same design and operation of the single-seater to its pilots.The difference in times is then attributable to the skills of the drivers,but considering the data ...The IndyCar series distinguishes itself by providing the same design and operation of the single-seater to its pilots.The difference in times is then attributable to the skills of the drivers,but considering the data from the races could test this assumption.The objective of this work was to establish a trajectory model to predict race times.A cross-sectional,correlational,and explanatory work was carried out with a sample of 18,474 records in the period from 2020 to 2023 of the IndyCar series.The results show that the time span predicts the time differences.In relation to the studies of acceptance of the technology,the adjustment of this to human capacities to explain the time differences in the series of racing cars is discussed.展开更多
INTO THE VOID An image captured by the Beijing Aerospace Control Center shows Shenzhou-18 astronaut Li Cong going out for extravehicular activities on July 3.The taikonauts,the nickname for Chinese astronauts,aboard C...INTO THE VOID An image captured by the Beijing Aerospace Control Center shows Shenzhou-18 astronaut Li Cong going out for extravehicular activities on July 3.The taikonauts,the nickname for Chinese astronauts,aboard China's Tiangong space station completed their second spacewalk that day.展开更多
In order to determine the reasonable completed dead load state in earth-anchored cable-stayed bridges,a practical method is proposed. The method is based on the rigidly supported continuous beam method and the feasibl...In order to determine the reasonable completed dead load state in earth-anchored cable-stayed bridges,a practical method is proposed. The method is based on the rigidly supported continuous beam method and the feasible zone method,emphasizing on the mutual effect between the self-anchored structural parts and the earth-anchored ones. Three cable-stayed bridge models are designed with the main spans of 1 400 m,including a partially earth-anchored cable-stayed bridge,a cable-stayed-suspension bridge and a fully selfanchored cable-stayed bridge,in which the C50 concrete and Q345 steel are adopted. The partially earthanchored cable-stayed bridge and the cable-stayed-suspension bridge secure lower compressive force in the girder than the fully self-anchored cable-stayed bridge by 25 percent at least. The same is for the material consumption of the whole bridge. Furthermore,the anchor volume is more than 20% lower in the partially earthanchored cable-stayed bridge than that in the cable-stayed-suspension bridge. Consequently,the practical span of cable-stayed bridges can be accordingly extended.展开更多
A hydro-dynamic model is established on basis of MIKE21 FM to simulate the hydro-dynamic characteristics of Xinghua Bay and investigate the influence of reclamation project on the tidal elevation and tidal currents. T...A hydro-dynamic model is established on basis of MIKE21 FM to simulate the hydro-dynamic characteristics of Xinghua Bay and investigate the influence of reclamation project on the tidal elevation and tidal currents. Tidal elevation data was obtained at the six tide gauge stations around the Xinghua Bay, and another six current stations were established to observe the tidal current velocity and direction. Validation shows that the model-simulated tidal elevation and tidal currents agree well with observations made at different stations. Predictions are made according to the reclamation project proposed in the regional marine planning of Hanjiang Industrial Park around the port in Putian City. The variations of hydro-dynamic factors, such as tide, current velocity and direction and tidal influx are obtained, and the adverse effect of reclamation on marine environment is discussed. It is shown that the tidal level inside the Xinghua Bay during high tide decreases after the reclamation project is completed. The tidal currents during flooding tide generally decrease in the southeast of the reclamation region, with the maximum decreasing amplitude reaching 0.44 m s^(-1). On the other hand, the tidal currents during flooding tide increase around the southeast and southwest corners of the reclamation region. The tidal currents during ebb tide increase around the southeast and southwest corners of the reclamation region, with the maximum increasing amplitude attaining 0.18 m s^(-1). The results in this paper can give some guidance for the marine environment management and the effective utilization of land in Putian.展开更多
This paper summarizes the parameter estimation of systems with set-valued signals, which can be classified to three catalogs: one-time completed algorithms, iterative methods and recursive algorithms. For one-time com...This paper summarizes the parameter estimation of systems with set-valued signals, which can be classified to three catalogs: one-time completed algorithms, iterative methods and recursive algorithms. For one-time completed algorithms, empirical measure method is one of the earliest methods to estimate parameters by using set-valued signals, which has been applied to the adaptive tracking of periodic target signals. The iterative methods seek numerical solutions of the maximum likelihood estimation, which have been applied to both complex diseases diagnosis and radar target recognition. The recursive algorithms are constructed via stochastic approximation and stochastic gradient methods, which have been applied to adaptive tracking of non-periodic signals.展开更多
Exact solutions with three-wave form including three solitary wave, breather-type two-solitary wave, doubly breather-type of solitary wave, double-periodic kind of solitary wave are obtained using bilinear form and ex...Exact solutions with three-wave form including three solitary wave, breather-type two-solitary wave, doubly breather-type of solitary wave, double-periodic kind of solitary wave are obtained using bilinear form and extended threewave approach with the aid of Maple. It is important that completed elastic collision, non-completed elastic collision,and fusion of three waves are investigated, respectively.展开更多
In this paper,we generalize the renowned Ciric and Caristi type fixed point theorem and some corollaries.Then we give an example to illustrate our result is really better than the theorem.
Since undertaking its first project abroad,the Zinder water supply project in Nigel,in 2003,the China Railway 20th Bureau Group(CR20G)has completed nearly 100 projects in 17 countries along the Belt and Road.
Calibration of the relationship between the scattering angle and the CCD pixel is a key part of achieving accurate measurements of rainbow refractometry.A novel self-calibrated global rainbow refractometry system base...Calibration of the relationship between the scattering angle and the CCD pixel is a key part of achieving accurate measurements of rainbow refractometry.A novel self-calibrated global rainbow refractometry system based on illumination by two lasers of different wavelengths is proposed.The angular calibration and refractive index measurement of two wavelengths can be completed simultaneously without extra measurement devices.The numerical and experimental results show the feasibility and high precision of the self-calibration method,which enables the rainbow refractometry to be implemented in a more powerful and convenient way.The self-calibrated rainbow system is successfully applied to measure the refractive indices of ethanol-water solutions with volume concentrations of 10% to 60%.展开更多
Little is known about the association between parity and the risk of ovarian cysts. The aim of this study was to examine the association between parity and the risk of ovarian cysts among a population of Chinese women...Little is known about the association between parity and the risk of ovarian cysts. The aim of this study was to examine the association between parity and the risk of ovarian cysts among a population of Chinese women. A total of 20 502 women aged 45–86 years from the Dongfeng-Tongji Cohort study completed baseline questionnaires, medical examination and provided baseline blood samples. Participants were categorized into four groups according to parity（one, two, three, and four or more live births）. Logistic regression models were used to investigate the association between parity and the risk of ovarian cysts. The prevalence of ovarian cysts in the study population was 4.0%（816/20 502）. Increasing parity was associated with decreasing risk of ovarian cysts without adjustment for any covariates and after age-adjusted model（P〈0.001）. After adjusting for potential confounders, women who had had four or more live births had lower risk of ovarian cysts（OR： 0.51; 95% CI： 0.27–0.96） compared with women who had had one live birth. There was a consistent but non-significant decreased risk of ovarian cysts for women who had had two, and three live births（OR： 0.85; 95% CI： 0.68–1.05） and（OR： 0.84; 95% CI： 0.59–1.20） respectively compared with women who had had one live birth. It was concluded that higher parity was associated with decreasing risk of ovarian cysts in this population of Chinese women. These findings could be helpful in decision making in clinical practice for gynecologists when evaluating women suspected to have ovarian cysts.展开更多
Tomas Lindahl completed his medical studies at Karolinska Institute in 1970.Yet,his work has always been dedicated to unraveling fundamental mechanisms of DNA decay and DNA repair.His research is characterized with gr...Tomas Lindahl completed his medical studies at Karolinska Institute in 1970.Yet,his work has always been dedicated to unraveling fundamental mechanisms of DNA decay and DNA repair.His research is characterized with groundbreaking discoveries on the instability of our genome,the identification of novel DNA repair activities,the characterization of DNA repair pathways,and the association to diseases,throughout his 40 years of scientific career.展开更多
Aerodynamic force can lead to the strong structural vibration of flying aircraft at a high speed. This harmful vibration can bring damage or failure to the electronic equipment fixed in aircraft. It is necessary to pr...Aerodynamic force can lead to the strong structural vibration of flying aircraft at a high speed. This harmful vibration can bring damage or failure to the electronic equipment fixed in aircraft. It is necessary to predict the structural dynamic response in the design course. This paper presents a new numerical algorithm and scheme to solve the structural dynamics responses when considering fluid–structure interaction（FSI）. Numerical simulation for a free-flying structural model in transonic speed is completed. Results show that the small elastic deformation of the structure can greatly affect the FSI. The FSI vibration tests are carried out in a transonic speed windtunnel for checking numerical theory and algorithms, and the wind-tunnel test results well accord with that of the numerical simulation. This indicates that the presented numerical method can be applied to predicting the structural dynamics responses when containing the FSI.展开更多
基金This project,No.2011ZA05,is supported by the State Key Laboratory of Subtropical Building Science,South China University of Technology,Guangzhou,China
文摘In order to quantitatively study the seismic absorption effect of the cushion on a superstructure, a numerical simulation and parametric study are carried out on the overall FEA model of a rigid-pile composite foundation in ABAQUS. A simulation of a shaking table test on a rigid mass block is first completed with ABAQUS and EERA, and the effectiveness of the Drucker-Prager constitutive model and the finite-infinite element coupling method is proved. Dynamic time-history analysis of the overall model under frequent and rare earthquakes is carried out using seismic waves from the El Centro, Kobe, and Bonds earthquakes. The different responses of rigid-pile composite foundations and pile-raft foundations are discussed. Furthermore, the influence of thickness and modulus of cushion, and ground acceleration on the seismic absorption effect of the cushion are analyzed. The results show that： 1） the seismic absorption effect of a cushion is good under rare earthquakes, with an absorption ratio of about 0.85; and 2） the seismic absorption effect is strongly affected by cushion thickness and ground acceleration.
文摘TWINDELIVERIES The Commercial Aircraft Corp.of China Ltd.(COMAC)delivers two C919 planes,China's first domestically produced large passenger aircraft,to Air China and China Southern Airlines at COMAC's manufacturing center in Shanghai on August 28.This was the first time these two airlines received the C919.To date,the COMAC has delivered nine C919 aircraft,seven of which went to China Eastern Airlines.Since the first C919 plane completed its maiden commercial flight in May 2023,the C919 fleet has successfully completed more than 3,000 flights,facilitating over 400,000 passenger trips.
文摘HIGH LIGHT!The High Energy Photon Source(HEPS)under construction in Beijing on August 18.The project is expected to be ready for operation by the end of 2025.Once completed,the HEPS will be able to emit light that is 1 trillion times brighter than the sun,and will be open to users in fields such as aerospace,energy,environment,life science and pharmaceuticals.
文摘The IndyCar series distinguishes itself by providing the same design and operation of the single-seater to its pilots.The difference in times is then attributable to the skills of the drivers,but considering the data from the races could test this assumption.The objective of this work was to establish a trajectory model to predict race times.A cross-sectional,correlational,and explanatory work was carried out with a sample of 18,474 records in the period from 2020 to 2023 of the IndyCar series.The results show that the time span predicts the time differences.In relation to the studies of acceptance of the technology,the adjustment of this to human capacities to explain the time differences in the series of racing cars is discussed.
文摘INTO THE VOID An image captured by the Beijing Aerospace Control Center shows Shenzhou-18 astronaut Li Cong going out for extravehicular activities on July 3.The taikonauts,the nickname for Chinese astronauts,aboard China's Tiangong space station completed their second spacewalk that day.
基金Sponsored by the National Basic Research Program of China(Grant No.2013CB036303)the National Natural Science Foundation of China(Grant No.51008223)
文摘In order to determine the reasonable completed dead load state in earth-anchored cable-stayed bridges,a practical method is proposed. The method is based on the rigidly supported continuous beam method and the feasible zone method,emphasizing on the mutual effect between the self-anchored structural parts and the earth-anchored ones. Three cable-stayed bridge models are designed with the main spans of 1 400 m,including a partially earth-anchored cable-stayed bridge,a cable-stayed-suspension bridge and a fully selfanchored cable-stayed bridge,in which the C50 concrete and Q345 steel are adopted. The partially earthanchored cable-stayed bridge and the cable-stayed-suspension bridge secure lower compressive force in the girder than the fully self-anchored cable-stayed bridge by 25 percent at least. The same is for the material consumption of the whole bridge. Furthermore,the anchor volume is more than 20% lower in the partially earthanchored cable-stayed bridge than that in the cable-stayed-suspension bridge. Consequently,the practical span of cable-stayed bridges can be accordingly extended.
基金supported by the Regional Marine Planning of Hanjiang Industrial Park around the port in Putian City
文摘A hydro-dynamic model is established on basis of MIKE21 FM to simulate the hydro-dynamic characteristics of Xinghua Bay and investigate the influence of reclamation project on the tidal elevation and tidal currents. Tidal elevation data was obtained at the six tide gauge stations around the Xinghua Bay, and another six current stations were established to observe the tidal current velocity and direction. Validation shows that the model-simulated tidal elevation and tidal currents agree well with observations made at different stations. Predictions are made according to the reclamation project proposed in the regional marine planning of Hanjiang Industrial Park around the port in Putian City. The variations of hydro-dynamic factors, such as tide, current velocity and direction and tidal influx are obtained, and the adverse effect of reclamation on marine environment is discussed. It is shown that the tidal level inside the Xinghua Bay during high tide decreases after the reclamation project is completed. The tidal currents during flooding tide generally decrease in the southeast of the reclamation region, with the maximum decreasing amplitude reaching 0.44 m s^(-1). On the other hand, the tidal currents during flooding tide increase around the southeast and southwest corners of the reclamation region. The tidal currents during ebb tide increase around the southeast and southwest corners of the reclamation region, with the maximum increasing amplitude attaining 0.18 m s^(-1). The results in this paper can give some guidance for the marine environment management and the effective utilization of land in Putian.
基金Supported by the National Natural Science Foundation of China(Nos.61803370,61622309)the China Postdoctoral Science Foundation(No.2018M630216)the National Key Research and Development Program of China(No.2016YFB0901902)
文摘This paper summarizes the parameter estimation of systems with set-valued signals, which can be classified to three catalogs: one-time completed algorithms, iterative methods and recursive algorithms. For one-time completed algorithms, empirical measure method is one of the earliest methods to estimate parameters by using set-valued signals, which has been applied to the adaptive tracking of periodic target signals. The iterative methods seek numerical solutions of the maximum likelihood estimation, which have been applied to both complex diseases diagnosis and radar target recognition. The recursive algorithms are constructed via stochastic approximation and stochastic gradient methods, which have been applied to adaptive tracking of non-periodic signals.
基金Supported by National Natural Science Foundation of China under Grant No.11361048Sichuan Educational Science Foundation under Grant No.12ZB069
文摘Exact solutions with three-wave form including three solitary wave, breather-type two-solitary wave, doubly breather-type of solitary wave, double-periodic kind of solitary wave are obtained using bilinear form and extended threewave approach with the aid of Maple. It is important that completed elastic collision, non-completed elastic collision,and fusion of three waves are investigated, respectively.
文摘In this paper,we generalize the renowned Ciric and Caristi type fixed point theorem and some corollaries.Then we give an example to illustrate our result is really better than the theorem.
文摘Since undertaking its first project abroad,the Zinder water supply project in Nigel,in 2003,the China Railway 20th Bureau Group(CR20G)has completed nearly 100 projects in 17 countries along the Belt and Road.
基金supported by the National Natural Science Foundation of China(No.51576177)the Major Program of the National Natural Science Foundation of China(No.51390491)+1 种基金the National Basic Research Program of China(No.2015CB251501)the Program of Introducing Talents of Discipline to University(No.B08026)
文摘Calibration of the relationship between the scattering angle and the CCD pixel is a key part of achieving accurate measurements of rainbow refractometry.A novel self-calibrated global rainbow refractometry system based on illumination by two lasers of different wavelengths is proposed.The angular calibration and refractive index measurement of two wavelengths can be completed simultaneously without extra measurement devices.The numerical and experimental results show the feasibility and high precision of the self-calibration method,which enables the rainbow refractometry to be implemented in a more powerful and convenient way.The self-calibrated rainbow system is successfully applied to measure the refractive indices of ethanol-water solutions with volume concentrations of 10% to 60%.
基金supported by grants from the National Natural Science Foundation of China(No.81273083)the Fundamental Research Funds for the Central Universities(No.2014TS051)
文摘Little is known about the association between parity and the risk of ovarian cysts. The aim of this study was to examine the association between parity and the risk of ovarian cysts among a population of Chinese women. A total of 20 502 women aged 45–86 years from the Dongfeng-Tongji Cohort study completed baseline questionnaires, medical examination and provided baseline blood samples. Participants were categorized into four groups according to parity（one, two, three, and four or more live births）. Logistic regression models were used to investigate the association between parity and the risk of ovarian cysts. The prevalence of ovarian cysts in the study population was 4.0%（816/20 502）. Increasing parity was associated with decreasing risk of ovarian cysts without adjustment for any covariates and after age-adjusted model（P〈0.001）. After adjusting for potential confounders, women who had had four or more live births had lower risk of ovarian cysts（OR： 0.51; 95% CI： 0.27–0.96） compared with women who had had one live birth. There was a consistent but non-significant decreased risk of ovarian cysts for women who had had two, and three live births（OR： 0.85; 95% CI： 0.68–1.05） and（OR： 0.84; 95% CI： 0.59–1.20） respectively compared with women who had had one live birth. It was concluded that higher parity was associated with decreasing risk of ovarian cysts in this population of Chinese women. These findings could be helpful in decision making in clinical practice for gynecologists when evaluating women suspected to have ovarian cysts.
文摘Tomas Lindahl completed his medical studies at Karolinska Institute in 1970.Yet,his work has always been dedicated to unraveling fundamental mechanisms of DNA decay and DNA repair.His research is characterized with groundbreaking discoveries on the instability of our genome,the identification of novel DNA repair activities,the characterization of DNA repair pathways,and the association to diseases,throughout his 40 years of scientific career.
基金supported by the National Natural Science Foundation of China(No.50875212)Specialized Research Fund(priority development area)for the Doctoral Program of Higher Education of China(No.20126102130004)
文摘Aerodynamic force can lead to the strong structural vibration of flying aircraft at a high speed. This harmful vibration can bring damage or failure to the electronic equipment fixed in aircraft. It is necessary to predict the structural dynamic response in the design course. This paper presents a new numerical algorithm and scheme to solve the structural dynamics responses when considering fluid–structure interaction（FSI）. Numerical simulation for a free-flying structural model in transonic speed is completed. Results show that the small elastic deformation of the structure can greatly affect the FSI. The FSI vibration tests are carried out in a transonic speed windtunnel for checking numerical theory and algorithms, and the wind-tunnel test results well accord with that of the numerical simulation. This indicates that the presented numerical method can be applied to predicting the structural dynamics responses when containing the FSI.
