Under earthquake action, different site conditions have a notable impact on the dynamic response of high-speed railway bridges after earthquakes, which in turn poses a threat to the running stability of trains in the ...Under earthquake action, different site conditions have a notable impact on the dynamic response of high-speed railway bridges after earthquakes, which in turn poses a threat to the running stability of trains in the post-earthquake period. Therefore, establishing a calculation method for the post-earthquake train speed threshold that considers the influence of different site characteristics is of great engineering significance. Taking the CRTS Ⅲ slab track as the research object, this study is based on the track irregularity root mean square rate(TRR), which the authors proposed earlier to quantify the track regularity level. Using the nonlinear least squares fitting method, the mapping relationship between the TRR and the postearthquake train running performance indicators on bridges is established. Furthermore, the influence of laws governing site categories and train speeds on post-earthquake train running performance on bridges is analyzed, and a train speed threshold for bridges based on running performance under random site conditions is proposed. The research results indicate that all train running performance indicators increase significantly with the increase of train operating speed;different site categories have a significant impact on post-earthquake track residual deformation and train running stability. The greater the amplitude of postearthquake track alignment residual deformation, the lower the threshold for the stable running speed of trains after the earthquake, with the speed threshold decreasing by up to 20%. The research outcomes can provide technical references for the post-earthquake safe operation and maintenance of high-speed railway bridges under complex site conditions, as well as the formulation of targeted train speed control schemes.展开更多
This paper expounds the quantitative tectonic indicators and some qualitative indicators of large earthquakes in the coast areas of Fujian, Guangdong, Taiwan and Hainan. The main quantitative indicators include uplift...This paper expounds the quantitative tectonic indicators and some qualitative indicators of large earthquakes in the coast areas of Fujian, Guangdong, Taiwan and Hainan. The main quantitative indicators include uplift amplitude of the Moho, Quaternary and Late Holocene coasts. The paper also gives a brief account of the research method on quantitative indicators of surface uplifted zones. Taiwan is a famous neotectonic zone and an area of large earthquakes in the world. There is only one large-earthquake area in each of Fujian, Guangdong and Hainan Provinces. Along the coast large earthquake areas there are certainly many remains of crustal activity. Among these remains, coast activity, taking the sea level as the accurate marker horizon, can determine not only the amplitude of coastal elevation and subsidence in a certain period, but also the cycle and rate of positive or negative movements.展开更多
The article established the HDRICE model by modifying the structure of the ORYZA1 model and revising its parameters by field experiments. The HDRICE model consists of the modules of morphological development of rice, ...The article established the HDRICE model by modifying the structure of the ORYZA1 model and revising its parameters by field experiments. The HDRICE model consists of the modules of morphological development of rice, daily dry matter accumulation and partitioning, daily CO2 assimilation of the canopy, leaf area, and tiller development. The model preferably simulated the dynamic rice development because of the thorough integration of the effects of temperature and light on the rates of rice development, photosynthesis, respiration, and. other ecophysiological processes. In addition, this model has attainable grain yield in the test experiment that showed the potential yield of cultivar Xieyou 46 ranged from 11 to 13 tons ha-~. Besides, the model was used to optimize the combinations of the transplanting date, seedling age and density for cultivar Xieyou 46 at Jinhua area, and the population quantitative indices to attain the potential yield such as maximum stems, effective panicles, filled grain number/leaf area, and so on. The result showed that the combination of transplanting date on July 25, seedling age of 35 days and base seedling density of 1.33 x 106ha-1 is the optimum combination for the second hybrid rice production in Jinhua County, China. And the maximum stems, the effective panicles, the filled grain per panicle, the peak of optimum LAI, LAI in later filling stage, and the filled grain number/leaf were 6.03×10^6ha, 3.99×10^6ha, 119.2, 8.59, 5-6, and 0.64, respectively.展开更多
Objective:To investigate the correlation between the peak pressure of contrast agent injection and tubal patency during real-time three-dimensional hysterosalpingo-contrast sonography.Methods:Seventy female patients w...Objective:To investigate the correlation between the peak pressure of contrast agent injection and tubal patency during real-time three-dimensional hysterosalpingo-contrast sonography.Methods:Seventy female patients who underwent real-time three-dimensional hysterosalpingo-contrast sonography of uterine and oviduct in the department of ultrasound medicine in our hospital were selected to measure the peak pressure in the examination process through the pressure injection device of contrast agent,to compare the pressure differences of different obturability patency degree of oviduct,and to draw a ROC curve to determine the optimal cut-off value of the peak pressure.Results:According to the different patency degree of fallopian tubes,the contrast results were divided into three groups:bilateral tubes unobstructed group,unilateral tube lesioned group and bilateral tubes lesioned group.The peak pressures of the three groups were(34.69±9.30)KPa,(52.71±18.55)KPa and(73.88±11.01)KPa,respectively.The area under the peak pressure ROC curve(AUC)of the"unilateral tube lesioned group"and"bilateral tubes lesioned group"was 0.785,the optimal cut-off value of the peak pressure was 51.90KPa,the area under the peak pressure ROC curve(AUC)of the"unilateral tube lesioned group"and"bilateral tubes lesioned group"was 0.851,and the optimal cut-off value of the peak pressure was 73.50KPa.Conclusion:The peak pressure of contrast agent injection in RT-3D-HyCoSy can be used as a quantitative index to deduce the patency degree of oviduct.There is a correlation between the peak pressure and the tubal patency.展开更多
Surface morphology of soil cracks is one of the important factors influencing the water evaporation rate in cracked soil in Yuanmou Dry-hot Valley Region,Southwest China. Quantitative study of the complicated surface ...Surface morphology of soil cracks is one of the important factors influencing the water evaporation rate in cracked soil in Yuanmou Dry-hot Valley Region,Southwest China. Quantitative study of the complicated surface morphology of soil cracks is a prerequisite for further studies of soil-cracking mechanisms. The present paper establishes a quantitative indicator system by application of concepts and methods originating from Fractal Geometry and Network Analysis. These indicators can effectively express the complicated features of soil-crack network structure. Furthermore,a series of values related to soil-crack morphology was obtained by image processing on field photos of soil-crack quads,and gradation criteria for the degree of development of soil cracks were determined. Finally,the changes in values of the morphological indicators under different degrees of development were analyzed in detail. Our results indicate that (1) the degree of development of soil cracks can be divided into five grades,i.e.,feeble development,slight development,medium development,intensive development and extremely intensive development; (2) the values of the indicators change predictably with increasing degree of development of soil cracks. The area density (Dc) increases,and both the area-weighted mean ratio of crack area to perimeter (AWMARP),which reflects the intensity of cracking,and the index r,which is related to the connectivity of a soil crack,grow uniformly (albeit with different forms). AWMRAP increases at a geometric rate while r shows logarithm-mic growth,indicating a gradual increase in theconnectivity of a soil crack. Nevertheless,the area-weighted mean of soil-crack fractal dimension (AWMFRAC) shows a decreasing trend,indicating a gradual decline in the complexity of cracks as area density increases.展开更多
The waiting spectra of the sets consisting of pairs of sequences with prescribed quantitative waiting time indicators are determined. More precisely,let R(x,y) and R(x,y) be the lower and upper quantitative waiting ti...The waiting spectra of the sets consisting of pairs of sequences with prescribed quantitative waiting time indicators are determined. More precisely,let R(x,y) and R(x,y) be the lower and upper quantitative waiting time indicators of y by x respectively in the symbolic space Σm(integer m 2) and define the level sets Sα,β={(x,y)∈Σ2m:R(x,y)=α,R(x,y)=β},where 0αβ∞,it is shown that the sets Sα,βare all of Hausdorff dimension 2.Besides,some further extensions of this result are also made.展开更多
Autonomous vehicles with self-evolution capabilities are expected to improve their performance through learning algorithms,to automatically adapt to the external environment.However,due to the infinity,complexity,and ...Autonomous vehicles with self-evolution capabilities are expected to improve their performance through learning algorithms,to automatically adapt to the external environment.However,due to the infinity,complexity,and variability of the actual traffic environment,it is necessary to develop quantitative representation indicators of scenario difficulty and generate targeted scenarios to ensure the evolution gradually,so as to quickly approach the performance limit of the algorithm.Therefore,this paper proposes a data-driven quantitative representation method of scenario difficulty.Specifically,the concept of environment agent is proposed,and a reinforcement learning method combined with mechanism knowledge is constructed for policy search to obtain an agent with an adversarial behavior.The model parameters of the environment agent at different stages in the training process are extracted to construct a policy group,and then agents with different adversarial intensities are obtained,which are used to realize data generation in different difficulty scenarios through the simulation environment.Finally,a data-driven scenario difficulty quantitative representation model is constructed,which is used to output the environment agent policy under different difficulties.Experimental results show the effectiveness of the proposed method.The result analysis shows that the proposed algorithm can generate reasonable and interpretable scenarios with high discrimination and can provide quantifiable difficulty representation without any expert logic rule design.Compared with the rule-based discrete scenario difficulty representation method,the proposed algorithm can achieve continuous difficulty representation.The video link is https://www.youtube.com/watch?v=GceGdqAm9Ys.展开更多
基金supported by the Science and Technology Research and Development Program Project of China Railway Group Limited (Grant No.2022-Major-17)the National Natural Science Foundation of China (Grant Nos.52578619,52178180)+2 种基金the National Key Research and Development Program of China (Grant No.2022YFC3004304)the Frontier Cross Research Project of Central South University (Grant No.2023QYJC006)the Natural Science Foundation of Hunan Province Funding Project (Grant No.2023JJ40724)。
文摘Under earthquake action, different site conditions have a notable impact on the dynamic response of high-speed railway bridges after earthquakes, which in turn poses a threat to the running stability of trains in the post-earthquake period. Therefore, establishing a calculation method for the post-earthquake train speed threshold that considers the influence of different site characteristics is of great engineering significance. Taking the CRTS Ⅲ slab track as the research object, this study is based on the track irregularity root mean square rate(TRR), which the authors proposed earlier to quantify the track regularity level. Using the nonlinear least squares fitting method, the mapping relationship between the TRR and the postearthquake train running performance indicators on bridges is established. Furthermore, the influence of laws governing site categories and train speeds on post-earthquake train running performance on bridges is analyzed, and a train speed threshold for bridges based on running performance under random site conditions is proposed. The research results indicate that all train running performance indicators increase significantly with the increase of train operating speed;different site categories have a significant impact on post-earthquake track residual deformation and train running stability. The greater the amplitude of postearthquake track alignment residual deformation, the lower the threshold for the stable running speed of trains after the earthquake, with the speed threshold decreasing by up to 20%. The research outcomes can provide technical references for the post-earthquake safe operation and maintenance of high-speed railway bridges under complex site conditions, as well as the formulation of targeted train speed control schemes.
基金This project was sponsored by the Joint Seismological Science Foundation Grant 2296203
文摘This paper expounds the quantitative tectonic indicators and some qualitative indicators of large earthquakes in the coast areas of Fujian, Guangdong, Taiwan and Hainan. The main quantitative indicators include uplift amplitude of the Moho, Quaternary and Late Holocene coasts. The paper also gives a brief account of the research method on quantitative indicators of surface uplifted zones. Taiwan is a famous neotectonic zone and an area of large earthquakes in the world. There is only one large-earthquake area in each of Fujian, Guangdong and Hainan Provinces. Along the coast large earthquake areas there are certainly many remains of crustal activity. Among these remains, coast activity, taking the sea level as the accurate marker horizon, can determine not only the amplitude of coastal elevation and subsidence in a certain period, but also the cycle and rate of positive or negative movements.
基金supported by the National Natural Science Foundation of China(69673044).
文摘The article established the HDRICE model by modifying the structure of the ORYZA1 model and revising its parameters by field experiments. The HDRICE model consists of the modules of morphological development of rice, daily dry matter accumulation and partitioning, daily CO2 assimilation of the canopy, leaf area, and tiller development. The model preferably simulated the dynamic rice development because of the thorough integration of the effects of temperature and light on the rates of rice development, photosynthesis, respiration, and. other ecophysiological processes. In addition, this model has attainable grain yield in the test experiment that showed the potential yield of cultivar Xieyou 46 ranged from 11 to 13 tons ha-~. Besides, the model was used to optimize the combinations of the transplanting date, seedling age and density for cultivar Xieyou 46 at Jinhua area, and the population quantitative indices to attain the potential yield such as maximum stems, effective panicles, filled grain number/leaf area, and so on. The result showed that the combination of transplanting date on July 25, seedling age of 35 days and base seedling density of 1.33 x 106ha-1 is the optimum combination for the second hybrid rice production in Jinhua County, China. And the maximum stems, the effective panicles, the filled grain per panicle, the peak of optimum LAI, LAI in later filling stage, and the filled grain number/leaf were 6.03×10^6ha, 3.99×10^6ha, 119.2, 8.59, 5-6, and 0.64, respectively.
基金Anhui province 2018 key research and opening plan project(No.1804h08020248)。
文摘Objective:To investigate the correlation between the peak pressure of contrast agent injection and tubal patency during real-time three-dimensional hysterosalpingo-contrast sonography.Methods:Seventy female patients who underwent real-time three-dimensional hysterosalpingo-contrast sonography of uterine and oviduct in the department of ultrasound medicine in our hospital were selected to measure the peak pressure in the examination process through the pressure injection device of contrast agent,to compare the pressure differences of different obturability patency degree of oviduct,and to draw a ROC curve to determine the optimal cut-off value of the peak pressure.Results:According to the different patency degree of fallopian tubes,the contrast results were divided into three groups:bilateral tubes unobstructed group,unilateral tube lesioned group and bilateral tubes lesioned group.The peak pressures of the three groups were(34.69±9.30)KPa,(52.71±18.55)KPa and(73.88±11.01)KPa,respectively.The area under the peak pressure ROC curve(AUC)of the"unilateral tube lesioned group"and"bilateral tubes lesioned group"was 0.785,the optimal cut-off value of the peak pressure was 51.90KPa,the area under the peak pressure ROC curve(AUC)of the"unilateral tube lesioned group"and"bilateral tubes lesioned group"was 0.851,and the optimal cut-off value of the peak pressure was 73.50KPa.Conclusion:The peak pressure of contrast agent injection in RT-3D-HyCoSy can be used as a quantitative index to deduce the patency degree of oviduct.There is a correlation between the peak pressure and the tubal patency.
基金supported by the National Key Technologies Research and Development Program in the Eleventh Five-Year Plan of China (Grant No.2008BAD98B02, 2006BAC01A11)the Western Light Program of Talents Cultivating of CAS (2008)+1 种基金the National Natural Sciences Foundation of China (Grant No. 30470297)the Foundation of Key Laboratory of Mountain Hazards and Surface Process, CAS
文摘Surface morphology of soil cracks is one of the important factors influencing the water evaporation rate in cracked soil in Yuanmou Dry-hot Valley Region,Southwest China. Quantitative study of the complicated surface morphology of soil cracks is a prerequisite for further studies of soil-cracking mechanisms. The present paper establishes a quantitative indicator system by application of concepts and methods originating from Fractal Geometry and Network Analysis. These indicators can effectively express the complicated features of soil-crack network structure. Furthermore,a series of values related to soil-crack morphology was obtained by image processing on field photos of soil-crack quads,and gradation criteria for the degree of development of soil cracks were determined. Finally,the changes in values of the morphological indicators under different degrees of development were analyzed in detail. Our results indicate that (1) the degree of development of soil cracks can be divided into five grades,i.e.,feeble development,slight development,medium development,intensive development and extremely intensive development; (2) the values of the indicators change predictably with increasing degree of development of soil cracks. The area density (Dc) increases,and both the area-weighted mean ratio of crack area to perimeter (AWMARP),which reflects the intensity of cracking,and the index r,which is related to the connectivity of a soil crack,grow uniformly (albeit with different forms). AWMRAP increases at a geometric rate while r shows logarithm-mic growth,indicating a gradual increase in theconnectivity of a soil crack. Nevertheless,the area-weighted mean of soil-crack fractal dimension (AWMFRAC) shows a decreasing trend,indicating a gradual decline in the complexity of cracks as area density increases.
文摘The waiting spectra of the sets consisting of pairs of sequences with prescribed quantitative waiting time indicators are determined. More precisely,let R(x,y) and R(x,y) be the lower and upper quantitative waiting time indicators of y by x respectively in the symbolic space Σm(integer m 2) and define the level sets Sα,β={(x,y)∈Σ2m:R(x,y)=α,R(x,y)=β},where 0αβ∞,it is shown that the sets Sα,βare all of Hausdorff dimension 2.Besides,some further extensions of this result are also made.
基金the National Key R&D Program of China under Grant No.2022YFB2502900the National Natural Science Foundation of China(Grant Number:U23B2061)+1 种基金the Fundamental Research Funds for the Central Universities of Chinathe Xiaomi Young Talent Program。
文摘Autonomous vehicles with self-evolution capabilities are expected to improve their performance through learning algorithms,to automatically adapt to the external environment.However,due to the infinity,complexity,and variability of the actual traffic environment,it is necessary to develop quantitative representation indicators of scenario difficulty and generate targeted scenarios to ensure the evolution gradually,so as to quickly approach the performance limit of the algorithm.Therefore,this paper proposes a data-driven quantitative representation method of scenario difficulty.Specifically,the concept of environment agent is proposed,and a reinforcement learning method combined with mechanism knowledge is constructed for policy search to obtain an agent with an adversarial behavior.The model parameters of the environment agent at different stages in the training process are extracted to construct a policy group,and then agents with different adversarial intensities are obtained,which are used to realize data generation in different difficulty scenarios through the simulation environment.Finally,a data-driven scenario difficulty quantitative representation model is constructed,which is used to output the environment agent policy under different difficulties.Experimental results show the effectiveness of the proposed method.The result analysis shows that the proposed algorithm can generate reasonable and interpretable scenarios with high discrimination and can provide quantifiable difficulty representation without any expert logic rule design.Compared with the rule-based discrete scenario difficulty representation method,the proposed algorithm can achieve continuous difficulty representation.The video link is https://www.youtube.com/watch?v=GceGdqAm9Ys.
