The pivot turning function of quadruped bionic robots can improve their mobility in unstructured environment.A kind of bionic flexible body mechanism for quadruped robot was proposed in this paper,which is composed of...The pivot turning function of quadruped bionic robots can improve their mobility in unstructured environment.A kind of bionic flexible body mechanism for quadruped robot was proposed in this paper,which is composed of one bionic spine and four pneumatic artificial muscles(PAMs).The coordinated movement of the bionic flexible body and the leg mechanism can achieve pivot turning gait.First,the pivot turning gait planning of quadruped robot was analyzed,and the coordinated movement sequence chart of pivot turning was presented.Then the kinematics modeling of leg side swing and body bending for pivot turning was derived,which should meet the condition of the coordinated movement between bionic flexible body and leg mechanism.The PAM experiment was conducted to analyze its contraction characteristic.The study on pivot turning of the quadruped robot will lay a theoretical foundation for the further research on dynamic walking stability of the quadruped robot in unstructured environment.展开更多
The walking creatures' athletic ability is related to their body' s musculoskeletal system.A kind of musculoskeletal body for quadruped robots is developed,which will be used to assist the leg mechanism to ach...The walking creatures' athletic ability is related to their body' s musculoskeletal system.A kind of musculoskeletal body for quadruped robots is developed,which will be used to assist the leg mechanism to achieve spinning gait in order to improve the robot mobility in unstructured environment.A bionic-flexible-spine model driven by pneumatic artificial muscles(PAMs) is proposed.Because the body has the flexible property,the robot can achieve spinning gait quickly,which is similar to walking creatures by coordinated movement between body bending and legs side-swing.The kinematics of the bending of the musculoskeletal body and side-swing of leg mechanism of quadruped robot for spinning gait are studied.According to the stability analysis of spinning gait,the relationship between body bending angle and leg swing angle can be determined.The PID controller is designed to conduct the bending experiment,and the bending characteristic of the musculoskeletal body is studied.Experimental results show that the biggest bending angle of the musculoskeletal body can reach 30°.展开更多
A real-valued negative selection algorithm with good mathematical foundation is presented to solve some of the drawbacks of previous approach. Specifically, it can produce a good estimate of the optimal number of dete...A real-valued negative selection algorithm with good mathematical foundation is presented to solve some of the drawbacks of previous approach. Specifically, it can produce a good estimate of the optimal number of detectors needed to cover the non-self space, and the maximization of the non-self coverage is done through an optimization algorithm with proven convergence properties. Experiments are performed to validate the assumptions made while designing the algorithm and to evaluate its performance.展开更多
South Africa is a country of many cultures. Before the first democratic elections in 1994, people of different cultures found it difficult to interact because of legislated racial segregation, which made it difficult ...South Africa is a country of many cultures. Before the first democratic elections in 1994, people of different cultures found it difficult to interact because of legislated racial segregation, which made it difficult for blacks to mix with whites in almost all spheres of life. The only place interaction could take place was in the workplace. As a result, children from different cultural groups had few opportunities to interact. This made it impossible for South African children to learn about the cultures of other racial groups. With the introduction of a democratic government, all segregation laws were relaxed and people mixed freely in all spheres of life. Intercultural communication became commonplace. This new scenario presented a challenge to many South African children, but despite the limits imposed before 1994, children from all racial groups associated successfully. Their ability to cope with this situation with so much more ease than adults was remarkable. This paper seeks to highlight the communication skills used by South African children from all cultural backgrounds to achieve intercultural competence in a relatively short space of time. The paper will further reflect on the impact made on African children by intercultural interaction and competence.展开更多
Parental effects occur whenever the phenotype of parents or the environment that they experience influences the phenotype and fitness of their offspring, In birds, parental effects are often mediated by the size and b...Parental effects occur whenever the phenotype of parents or the environment that they experience influences the phenotype and fitness of their offspring, In birds, parental effects are often mediated by the size and biochemical quality of the eggs in terms of maternally transferred components. Exogenous antioxidants are key egg components that accomplish crucial physiological functions during early life. Among these, vitamin E plays a vital role during prenatal development when the intense metabolism accompanying rapid embryo growth results in overproduction of pro-oxidant molecules. Studies of captive birds have demonstrated the positive effect of vitamin E supplementation on diverse phenotypic traits of hatchling and adult individuals, but its effects on embryo phenotype has never been investigated neither in captivity nor under a natural selection regime. In the present study, we experimentally tested the effect of the in ovo supplementation of vitamin E on morphological traits and oxidative status of yellow-legged gull (Larus michahellis) embryos. The supplementation of vitamin E promoted somatic growth in embryos soon before hatching, but did not affect their oxidative status. Our results suggest that maternally transferred vitamin E concentrations are optimized to prevent imbalances of oxidative status and the consequent raise of oxidative damage in yellow-legged gull embryos during prenatal development.展开更多
Enzymes are biomacromolecules responsible for the abundant chemical biotransformations that sustain life. Recently, biochemists have discovered that multiple conformations and numerous parallel paths are involved duri...Enzymes are biomacromolecules responsible for the abundant chemical biotransformations that sustain life. Recently, biochemists have discovered that multiple conformations and numerous parallel paths are involved during the processes catalyzed by enzymes. It is plausible that the entire macromolecular scaffold is involved in catalysis via cooperative motions that result in incredible catalytic efficiency. Moreover, some enzymes can very strongly bind the transition state with an association constant of up to 1024 M-1, suggesting that covalent bond formation is a possible process during the conversion of the transition state in enzyme catalysis, in addition to the concatenation of noncovalent interactions. Supramolecular chemistry provides fundamental knowledge about the relationships between the dynamic structures and functions of organized molecules. By tak-ing advantage of supramolecular concepts, numerous supramolecular enzyme mimics with complex and hierarchical structures have been designed and investigated. Through the study of supramolecular enzyme models, a great deal of information to aid our understanding of the mechanism of catalysis by natural enzymes has been acquired. With the development of supramolec-ular artificial enzymes, it is possible to replicate the features of natural enzymes with regards to their constitutional complexity and cooperative motions, and eventually decipher the conformation-based catalytic mystery of natural enzymes.展开更多
基金Supported by the National Natural Science Foundation of China(No.51375289)Shanghai Municipal National Natural Science Foundation of China(No.13ZR1415500)the Innovation Fund of Shanghai Education Commission(No.13YZ020)
文摘The pivot turning function of quadruped bionic robots can improve their mobility in unstructured environment.A kind of bionic flexible body mechanism for quadruped robot was proposed in this paper,which is composed of one bionic spine and four pneumatic artificial muscles(PAMs).The coordinated movement of the bionic flexible body and the leg mechanism can achieve pivot turning gait.First,the pivot turning gait planning of quadruped robot was analyzed,and the coordinated movement sequence chart of pivot turning was presented.Then the kinematics modeling of leg side swing and body bending for pivot turning was derived,which should meet the condition of the coordinated movement between bionic flexible body and leg mechanism.The PAM experiment was conducted to analyze its contraction characteristic.The study on pivot turning of the quadruped robot will lay a theoretical foundation for the further research on dynamic walking stability of the quadruped robot in unstructured environment.
基金Supported by the National Natural Science Foundation of China(No.51375289)Shanghai Municipal National Natural Science Foundation of China(No.13ZR1415500)Innovation Fund of Shanghai Education Commission(No.13YZ020)
文摘The walking creatures' athletic ability is related to their body' s musculoskeletal system.A kind of musculoskeletal body for quadruped robots is developed,which will be used to assist the leg mechanism to achieve spinning gait in order to improve the robot mobility in unstructured environment.A bionic-flexible-spine model driven by pneumatic artificial muscles(PAMs) is proposed.Because the body has the flexible property,the robot can achieve spinning gait quickly,which is similar to walking creatures by coordinated movement between body bending and legs side-swing.The kinematics of the bending of the musculoskeletal body and side-swing of leg mechanism of quadruped robot for spinning gait are studied.According to the stability analysis of spinning gait,the relationship between body bending angle and leg swing angle can be determined.The PID controller is designed to conduct the bending experiment,and the bending characteristic of the musculoskeletal body is studied.Experimental results show that the biggest bending angle of the musculoskeletal body can reach 30°.
基金Sponsored by the National Natural Science Foundation of China ( Grant No. 60671049 ), the Subject Chief Foundation of Harbin ( Grant No.2003AFXXJ013), the Education Department Research Foundation of Heilongjiang Province(Grant No.10541044,1151G012) and the Postdoctor Founda-tion of Heilongjiang(Grant No.LBH-Z05092).
文摘A real-valued negative selection algorithm with good mathematical foundation is presented to solve some of the drawbacks of previous approach. Specifically, it can produce a good estimate of the optimal number of detectors needed to cover the non-self space, and the maximization of the non-self coverage is done through an optimization algorithm with proven convergence properties. Experiments are performed to validate the assumptions made while designing the algorithm and to evaluate its performance.
文摘South Africa is a country of many cultures. Before the first democratic elections in 1994, people of different cultures found it difficult to interact because of legislated racial segregation, which made it difficult for blacks to mix with whites in almost all spheres of life. The only place interaction could take place was in the workplace. As a result, children from different cultural groups had few opportunities to interact. This made it impossible for South African children to learn about the cultures of other racial groups. With the introduction of a democratic government, all segregation laws were relaxed and people mixed freely in all spheres of life. Intercultural communication became commonplace. This new scenario presented a challenge to many South African children, but despite the limits imposed before 1994, children from all racial groups associated successfully. Their ability to cope with this situation with so much more ease than adults was remarkable. This paper seeks to highlight the communication skills used by South African children from all cultural backgrounds to achieve intercultural competence in a relatively short space of time. The paper will further reflect on the impact made on African children by intercultural interaction and competence.
文摘Parental effects occur whenever the phenotype of parents or the environment that they experience influences the phenotype and fitness of their offspring, In birds, parental effects are often mediated by the size and biochemical quality of the eggs in terms of maternally transferred components. Exogenous antioxidants are key egg components that accomplish crucial physiological functions during early life. Among these, vitamin E plays a vital role during prenatal development when the intense metabolism accompanying rapid embryo growth results in overproduction of pro-oxidant molecules. Studies of captive birds have demonstrated the positive effect of vitamin E supplementation on diverse phenotypic traits of hatchling and adult individuals, but its effects on embryo phenotype has never been investigated neither in captivity nor under a natural selection regime. In the present study, we experimentally tested the effect of the in ovo supplementation of vitamin E on morphological traits and oxidative status of yellow-legged gull (Larus michahellis) embryos. The supplementation of vitamin E promoted somatic growth in embryos soon before hatching, but did not affect their oxidative status. Our results suggest that maternally transferred vitamin E concentrations are optimized to prevent imbalances of oxidative status and the consequent raise of oxidative damage in yellow-legged gull embryos during prenatal development.
基金financial support from the National Natural Science Foundation of China(91027023,21234004,21274051,21221063,21004028)the 111 project(B06009)
文摘Enzymes are biomacromolecules responsible for the abundant chemical biotransformations that sustain life. Recently, biochemists have discovered that multiple conformations and numerous parallel paths are involved during the processes catalyzed by enzymes. It is plausible that the entire macromolecular scaffold is involved in catalysis via cooperative motions that result in incredible catalytic efficiency. Moreover, some enzymes can very strongly bind the transition state with an association constant of up to 1024 M-1, suggesting that covalent bond formation is a possible process during the conversion of the transition state in enzyme catalysis, in addition to the concatenation of noncovalent interactions. Supramolecular chemistry provides fundamental knowledge about the relationships between the dynamic structures and functions of organized molecules. By tak-ing advantage of supramolecular concepts, numerous supramolecular enzyme mimics with complex and hierarchical structures have been designed and investigated. Through the study of supramolecular enzyme models, a great deal of information to aid our understanding of the mechanism of catalysis by natural enzymes has been acquired. With the development of supramolec-ular artificial enzymes, it is possible to replicate the features of natural enzymes with regards to their constitutional complexity and cooperative motions, and eventually decipher the conformation-based catalytic mystery of natural enzymes.