In this study, Sprague-Dawley rats were immobilized to a frame for 3 hours a day for 21 days to establish a model of chronic immobilization stress. The body weight and food intake of rats subjected to chronic immobili...In this study, Sprague-Dawley rats were immobilized to a frame for 3 hours a day for 21 days to establish a model of chronic immobilization stress. The body weight and food intake of rats subjected to chronic immobilization stress were significantly decreased compared with the control group. Dual-labeling immunofluorescence revealed that the expression of leptin receptor and the co-localization coeffient in these leptic receptor neurons in the arcuate nucleus of the hypothalamus were both upregulated, while the number of neuropeptide Y neurons was decreased. Chronic immobilization stress induced high expression of leptin receptor in the arcuate nucleus and suppressed the synthesis and secretion of neuropeptide Y, thereby disrupting the pathways in the arcuate nucleus that regulate feeding behavior, resulting in diminished food intake and reduced body weight.展开更多
Quadruped robot is considered to be the most practical locomotion machine to negotiate uneven terrain, and shows superb stability during static walking. To improve the ability to go over rough terrain, this paper is f...Quadruped robot is considered to be the most practical locomotion machine to negotiate uneven terrain, and shows superb stability during static walking. To improve the ability to go over rough terrain, this paper is focused on the stable walking and balance control of quadruped robots. 24 kinds of walking gaits are analyzed in order to derive the most stable and smoothest walking gait. Considering the inefficiency to model a terrain by its specified appearance, a uniform terrain model is established and by means of kinematic analysis, a method to adjust the body posture and center of gravity （COG） height is presented. Simulations demonstrate the effectiveness of the proposed meth- od and the improvement of the adaptation of quadruped robots on rough terrain.展开更多
Effect of slope inclination on step friction coefficient of human being was studied by gait friction tester developed by Henan University of Science and Technology.It is beneficial to improving the safety of human bei...Effect of slope inclination on step friction coefficient of human being was studied by gait friction tester developed by Henan University of Science and Technology.It is beneficial to improving the safety of human beings while walking on a ramp.Based on the trajectory of mass center of body(MCOB)and the mechanical analysis of human body while walking,conclusion could be drawn that the required step frictional coefficient(RSFC)exhibited an"M"shaped curve during the foot contacting with the ground and got its maximum and minimum values when MCOB of the subject was at the highest and lowest position respectively.Moreover,the first peak of RSFC decreases firstly and then increases,while the second peak of RSFC increases with the increase of slope inclination at the experimental condition.The position of pivotal point is decided by the relative size of slope inclination and the angle between the plumb line through MCOB and the line from foot to MCOB.展开更多
针对翼身融合布局(Blended Wing Body,BWB)民机设计中参考翼型缺乏的问题,采用自由变形(Free Form Deformation,FFD)参数化方法,结合Kriging代理模型、遗传算法和松散式代理模型管理框架,构建了翼型气动优化设计平台。根据BWB布局民机...针对翼身融合布局(Blended Wing Body,BWB)民机设计中参考翼型缺乏的问题,采用自由变形(Free Form Deformation,FFD)参数化方法,结合Kriging代理模型、遗传算法和松散式代理模型管理框架,构建了翼型气动优化设计平台。根据BWB布局民机中央机体和外翼不同的功能需求和总体约束,确定了中央机体和外翼翼型不同的优化目标和约束条件,针对某BWB布局民机开展了中央机体和外翼翼型气动优化设计。优化设计的中央机体翼型满足装载厚度、升阻比和升力设计要求,并提供翼身融合布局设计极为需要的俯仰抬头力矩,具有前加载和后卸载特征;外翼翼型在低头力矩不增加的前提下,激波强度减弱,气动效率提高。研究结果表明,本文建立的优化设计平台为BWB民机翼型设计提供了有效工具,并可适用于各种要求的翼型设计。展开更多
基金supported by the National Natural Science Foundation of China,No.30672578,81072756and81202644China National Funds for Distinguished Young Scientists,No.30825046+2 种基金Program for Innovative Research Team in Beijing University of Chinese Medicine,No.2011CXTD-07Program for University Key Teacher of Hebei Medical UniversitySpecialized Research Fund for the Doctoral Program of Higher Education,No.20121323120016
文摘In this study, Sprague-Dawley rats were immobilized to a frame for 3 hours a day for 21 days to establish a model of chronic immobilization stress. The body weight and food intake of rats subjected to chronic immobilization stress were significantly decreased compared with the control group. Dual-labeling immunofluorescence revealed that the expression of leptin receptor and the co-localization coeffient in these leptic receptor neurons in the arcuate nucleus of the hypothalamus were both upregulated, while the number of neuropeptide Y neurons was decreased. Chronic immobilization stress induced high expression of leptin receptor in the arcuate nucleus and suppressed the synthesis and secretion of neuropeptide Y, thereby disrupting the pathways in the arcuate nucleus that regulate feeding behavior, resulting in diminished food intake and reduced body weight.
基金Supported by the National High Technology Research and Development Program of China(863Program)(2011AA041002)
文摘Quadruped robot is considered to be the most practical locomotion machine to negotiate uneven terrain, and shows superb stability during static walking. To improve the ability to go over rough terrain, this paper is focused on the stable walking and balance control of quadruped robots. 24 kinds of walking gaits are analyzed in order to derive the most stable and smoothest walking gait. Considering the inefficiency to model a terrain by its specified appearance, a uniform terrain model is established and by means of kinematic analysis, a method to adjust the body posture and center of gravity （COG） height is presented. Simulations demonstrate the effectiveness of the proposed meth- od and the improvement of the adaptation of quadruped robots on rough terrain.
基金supported by the National Natural Science Foundation of China(Grant Nos.U1034002 and 51175149)
文摘Effect of slope inclination on step friction coefficient of human being was studied by gait friction tester developed by Henan University of Science and Technology.It is beneficial to improving the safety of human beings while walking on a ramp.Based on the trajectory of mass center of body(MCOB)and the mechanical analysis of human body while walking,conclusion could be drawn that the required step frictional coefficient(RSFC)exhibited an"M"shaped curve during the foot contacting with the ground and got its maximum and minimum values when MCOB of the subject was at the highest and lowest position respectively.Moreover,the first peak of RSFC decreases firstly and then increases,while the second peak of RSFC increases with the increase of slope inclination at the experimental condition.The position of pivotal point is decided by the relative size of slope inclination and the angle between the plumb line through MCOB and the line from foot to MCOB.
文摘针对翼身融合布局(Blended Wing Body,BWB)民机设计中参考翼型缺乏的问题,采用自由变形(Free Form Deformation,FFD)参数化方法,结合Kriging代理模型、遗传算法和松散式代理模型管理框架,构建了翼型气动优化设计平台。根据BWB布局民机中央机体和外翼不同的功能需求和总体约束,确定了中央机体和外翼翼型不同的优化目标和约束条件,针对某BWB布局民机开展了中央机体和外翼翼型气动优化设计。优化设计的中央机体翼型满足装载厚度、升阻比和升力设计要求,并提供翼身融合布局设计极为需要的俯仰抬头力矩,具有前加载和后卸载特征;外翼翼型在低头力矩不增加的前提下,激波强度减弱,气动效率提高。研究结果表明,本文建立的优化设计平台为BWB民机翼型设计提供了有效工具,并可适用于各种要求的翼型设计。
