Based on the aerodynamics and vehicle dynamics, the aerodynamic performances and vehicle dynamic characteristics of two high-speed trains passing each other on the ground, embankment and bridge are studied. Firstly, a...Based on the aerodynamics and vehicle dynamics, the aerodynamic performances and vehicle dynamic characteristics of two high-speed trains passing each other on the ground, embankment and bridge are studied. Firstly, a train aerodynamic model and a vehicle dynamic model are established. Through the simulation of the two models, the pressure waves, aerodynamic forces, and vehicle dynamic responses are obtained. Then, the pressure waves and aero- dynamic forces on different foundations are compared. The results show that the variation trends of pressure wave and aerodynamic forces of trains passing each other on different foundations are almost similar. The peak-to-peak differ- ences in pressure wave and aerodynamic force are below 4% and 3% in three cases in open air. Besides, the differences of security indexes, including coefficient of derailment, wheel unloading rate, the wheelset lateral force, and the wheel- rail vertical force, are below 2% among the three cases; the differences of comfort indexes, including the lateral acceleration and the vertical acceleration, are also below 2%. It is concluded that the dynamic performances of trains pass- ing each other are influenced little by different foundations in open air.展开更多
A new method is proposed to numerically simulate problems of trains passing by each other at the same speed, and is implemented in UDF language of commercial software Fluent. Because only a half of the computational d...A new method is proposed to numerically simulate problems of trains passing by each other at the same speed, and is implemented in UDF language of commercial software Fluent. Because only a half of the computational domain is required and the dynamic mesh technique is avoided, the computational efficiency is greatly improved. A two-dimensional test case is used for validation, which shows that the flow field and the pressure wave during the train-passing events can be correctly calculated by this new method. This method can be easily extended to three-dimensional simulations, to deal with practical problems.展开更多
Objective：To analyze the diagnostic consistency of Chinese medicine（CM） specialists in patients with cardiovascular disease and to study syndrome classification and identification based on the multi-label learning ...Objective：To analyze the diagnostic consistency of Chinese medicine（CM） specialists in patients with cardiovascular disease and to study syndrome classification and identification based on the multi-label learning method.Methods：Using self-developed CM clinical scales to collect cases,inquiry information,complexity,tongue manifestation and pulse manifestation were assessed.The number of cases collected was 2,218.Firstly,each case was differentiated by two CM specialists according to the same diagnostic criteria.The consistency of the diagnosis based on Cohen’s Kappa coefficient was analyzed.Secondly,take the same diagnosis syndromes of two specialists as the results of the cases.According to injury information in the CM scale ＂yes＂ or ＂no＂ was assigned ＂1＂ or ＂0＂,and according to the syndrome type in each case ＂yes＂ or ＂no＂ was assigned ＂1＂ or ＂0＂.CM information data on cardiovascular disease cases were established.We studied CM syndrome classification and identification based on the relevant feature for each label（REAL） leaming method,and the diagnostic rate of the syndrome was studied using the REAL method when the number of features selected was 5,10,15,20,30,50,70,and 100,respectively.Results：The syndromes with good diagnostic consistency were Heart（Xin）-qi deficiency,Heart-yang deficiency,Heart-yin deficiency,phlegm,stagnation of blood and stagnation of qi.Syndromes with poor diagnostic consistency were heartblood deficiency and blood deficiency of Heart and Liver（Gan）.The highest diagnostic rates using the REAL method were Heart-yang deficiency followed by Heart-qi deficiency.A different number of features,such as 5,10,15,20,30,40,50,70,and 100,respectively,were selected and the diagnostic accuracy based on five features showed the highest diagnostic accuracy.The top five features which had a strong correlation with the syndromes were in accordance with the CM theory.Conclnsions：CM syndrome differentiation is strongly subjective and it is difficult to obtain good diagnostic consistency.The REAL method fully considers the relationship between syndrome types and injury symptoms,and is suitable for the establishment of models for CM syndrome classification and identification.This method can probably provide the prerequisite for objectivity and standardization of CM differentiation.展开更多
It is found with the method of multiple scales that there exists a new periodical processwith long period T_1= 2π(Δω~2-f^2ω)^(1/2) when f= ω_e^2A_r/g and Δω/ω=ω-ω_e/ω are O(ε), whereg is the gravitational ...It is found with the method of multiple scales that there exists a new periodical processwith long period T_1= 2π(Δω~2-f^2ω)^(1/2) when f= ω_e^2A_r/g and Δω/ω=ω-ω_e/ω are O(ε), whereg is the gravitational acceleration, ω_e half of the driving frequency, A. the driving ampli-tude, ω the frequency of (0, 1) mode of the water trough. Suggest that φ which is corre-lativc with the complex amplitude of velocity potential is a function of θ and ?φ/?θ is O(ω~3),where θ satisfies θ(t + T_1) =θ(t), e.g. θ=?/Ω sinΩ_t (Ω=2π/T_1). The NLS equation of theφ(x,θ) is obtained. The phenomena of passing--through and oscil- lating about each other ofa pair of solitary waves in a rectangular water trough can be explained.展开更多
目的在“骨肉不相亲”理论指导下,比较废用性骨质疏松症大鼠股骨、腓肠肌中果蝇母本抗生存因子蛋白2/3(small mother against decapentaplegic 2/3,Smad2/3)、特异性蛋白1(specificity protein 1,SP1)表达在中医不同治法下的影响,分析...目的在“骨肉不相亲”理论指导下,比较废用性骨质疏松症大鼠股骨、腓肠肌中果蝇母本抗生存因子蛋白2/3(small mother against decapentaplegic 2/3,Smad2/3)、特异性蛋白1(specificity protein 1,SP1)表达在中医不同治法下的影响,分析中医药对其的防治机制。方法将60只大鼠随机分为正常组、模型组、补肾组、健脾组、补肾健脾组、西药组6组,并适应性喂养1周,造模组采用尾吊法建立模型,5周后取大鼠的腹主动脉血清、股骨及腓肠肌。通过骨密度检测和对股骨远端横断面处的骨形态进行三维重建观察比较各组大鼠股骨组织结构变化,评估骨质流失情况。采用HE染色和Masson染色观察大鼠腓肠肌组织的形态学变化。采用ELISA法检测各组大鼠血清碱性磷酸酶(alkaline phosphatase,ALP)、抗酒石酸酸性磷酸酶(tartrate resistant acid phosphatase,TRACP)水平和股骨、腓肠肌中Smad2/3、SP1蛋白表达。结果与正常组比较,模型组大鼠股骨骨密度显著降低(P<0.01),骨微结构破坏明显;腓肠肌肌纤维萎缩,排列疏松;血清ALP水平显著降低、TRACP水平显著升高(P<0.01);股骨与腓肠肌中Smad2/3、SP1蛋白表达显著升高(P<0.01)。与模型组比较,各给药组股骨骨密度明显升高(P<0.05),骨微结构修复明显;腓肠肌肌纤维增粗,肌间隙减小;ALP水平明显升高(P<0.05,P<0.01)。与模型组比较,补肾健脾组和西药组TRACP水平降低最显著(P<0.01),其次是补肾组(P<0.05);各给药组股骨与腓肠肌中Smad2/3、SP1蛋白表达显著降低(P<0.01)。结论废用性骨质疏松症的发生、发展可能与骨骼及肌肉中Smad2/3、SP1蛋白表达的升高有关,二者的高表达可能会导致骨-肌失衡。各中医治法对废用性骨质疏松症的防治作用可能与降低骨骼与肌肉中Smad2/3、SP1蛋白表达有关。展开更多
基金supported by the National Natural Science Foundations of China (Nos. 50823004 and 50821063)the "Eleventh Five-year Plan" National Science and Technology Support Plan(No. 2009BAG12A01-C09)
文摘Based on the aerodynamics and vehicle dynamics, the aerodynamic performances and vehicle dynamic characteristics of two high-speed trains passing each other on the ground, embankment and bridge are studied. Firstly, a train aerodynamic model and a vehicle dynamic model are established. Through the simulation of the two models, the pressure waves, aerodynamic forces, and vehicle dynamic responses are obtained. Then, the pressure waves and aero- dynamic forces on different foundations are compared. The results show that the variation trends of pressure wave and aerodynamic forces of trains passing each other on different foundations are almost similar. The peak-to-peak differ- ences in pressure wave and aerodynamic force are below 4% and 3% in three cases in open air. Besides, the differences of security indexes, including coefficient of derailment, wheel unloading rate, the wheelset lateral force, and the wheel- rail vertical force, are below 2% among the three cases; the differences of comfort indexes, including the lateral acceleration and the vertical acceleration, are also below 2%. It is concluded that the dynamic performances of trains pass- ing each other are influenced little by different foundations in open air.
文摘A new method is proposed to numerically simulate problems of trains passing by each other at the same speed, and is implemented in UDF language of commercial software Fluent. Because only a half of the computational domain is required and the dynamic mesh technique is avoided, the computational efficiency is greatly improved. A two-dimensional test case is used for validation, which shows that the flow field and the pressure wave during the train-passing events can be correctly calculated by this new method. This method can be easily extended to three-dimensional simulations, to deal with practical problems.
基金Supported by the National Natural Science Foundation of China(No.81173199)
文摘Objective：To analyze the diagnostic consistency of Chinese medicine（CM） specialists in patients with cardiovascular disease and to study syndrome classification and identification based on the multi-label learning method.Methods：Using self-developed CM clinical scales to collect cases,inquiry information,complexity,tongue manifestation and pulse manifestation were assessed.The number of cases collected was 2,218.Firstly,each case was differentiated by two CM specialists according to the same diagnostic criteria.The consistency of the diagnosis based on Cohen’s Kappa coefficient was analyzed.Secondly,take the same diagnosis syndromes of two specialists as the results of the cases.According to injury information in the CM scale ＂yes＂ or ＂no＂ was assigned ＂1＂ or ＂0＂,and according to the syndrome type in each case ＂yes＂ or ＂no＂ was assigned ＂1＂ or ＂0＂.CM information data on cardiovascular disease cases were established.We studied CM syndrome classification and identification based on the relevant feature for each label（REAL） leaming method,and the diagnostic rate of the syndrome was studied using the REAL method when the number of features selected was 5,10,15,20,30,50,70,and 100,respectively.Results：The syndromes with good diagnostic consistency were Heart（Xin）-qi deficiency,Heart-yang deficiency,Heart-yin deficiency,phlegm,stagnation of blood and stagnation of qi.Syndromes with poor diagnostic consistency were heartblood deficiency and blood deficiency of Heart and Liver（Gan）.The highest diagnostic rates using the REAL method were Heart-yang deficiency followed by Heart-qi deficiency.A different number of features,such as 5,10,15,20,30,40,50,70,and 100,respectively,were selected and the diagnostic accuracy based on five features showed the highest diagnostic accuracy.The top five features which had a strong correlation with the syndromes were in accordance with the CM theory.Conclnsions：CM syndrome differentiation is strongly subjective and it is difficult to obtain good diagnostic consistency.The REAL method fully considers the relationship between syndrome types and injury symptoms,and is suitable for the establishment of models for CM syndrome classification and identification.This method can probably provide the prerequisite for objectivity and standardization of CM differentiation.
基金Project supported by the National Natural Science Foundation of China
文摘It is found with the method of multiple scales that there exists a new periodical processwith long period T_1= 2π(Δω~2-f^2ω)^(1/2) when f= ω_e^2A_r/g and Δω/ω=ω-ω_e/ω are O(ε), whereg is the gravitational acceleration, ω_e half of the driving frequency, A. the driving ampli-tude, ω the frequency of (0, 1) mode of the water trough. Suggest that φ which is corre-lativc with the complex amplitude of velocity potential is a function of θ and ?φ/?θ is O(ω~3),where θ satisfies θ(t + T_1) =θ(t), e.g. θ=?/Ω sinΩ_t (Ω=2π/T_1). The NLS equation of theφ(x,θ) is obtained. The phenomena of passing--through and oscil- lating about each other ofa pair of solitary waves in a rectangular water trough can be explained.
