As space equipment become larger in size and more flexible,generalized mechanisms are being widely used in space-deployable structures.Dynamic modeling of large-scale generalized space-deployable mechanisms is challen...As space equipment become larger in size and more flexible,generalized mechanisms are being widely used in space-deployable structures.Dynamic modeling of large-scale generalized space-deployable mechanisms is challenging owing to the coupling between the deformation of flexible links and rigid body motion.This study develops a dynamic modeling method for generalized mechanisms using the local frame of the SE(3)Lie group.The model represents both rigid and flexible links within a unified Lie group setting.The expressions for the velocities of rigid links and deformation of flexible links are derived using the Lie algebra framework.The nonuniqueness of the degrees of freedom of generalized kinematic pairs is considered,and the velocity fields of kinematic pairs in different situations are expressed.The equations of motion are derived using Hamilton’s principle.Because the velocities are expressed in the local frame,the mass matrix in the equation is constant,which yields a compact and unified expression for the dynamic equation.A Lie group generalized-αtime integration method is adopted to ensure numerical stability and efficiency in simulating multibody systems with large rotations and deformations.Two numerical examples are studied to demonstrate a formulation that reflects the motion responses under varying configurations and loading conditions.This study broadens the application of the local frame of the Lie group formulation in space mechanisms and provides a new concept for dynamic modeling of generalized mechanisms.展开更多
An automatic patch snatching system is described which has three machine cells including dividing equipment, tackling equipment and patch removing equipment. The electromechanical integration design of in-piece tackli...An automatic patch snatching system is described which has three machine cells including dividing equipment, tackling equipment and patch removing equipment. The electromechanical integration design of in-piece tackling system based on the concept of generalized mechanisms is introduced. The design of the dividing equipment, the design of micro-feeding machine equipped with micro-level pressure sensor, and the realizing of computer path for patch snatching are investigated.展开更多
The perturbations to symmetries and adiabatic invariants for nonconservative systems of generalized classical mechanics axe studied. The exact inwriant in the form of Hojman from a particular Lie symmetry for an undis...The perturbations to symmetries and adiabatic invariants for nonconservative systems of generalized classical mechanics axe studied. The exact inwriant in the form of Hojman from a particular Lie symmetry for an undisturbed system of generalized mechanics is given. Based on the concept of high-order adiabatic invaxiant in generalized mechanics, the perturbation to Lie symmetry for the system under the action of small disturbance is investigated, and a new adiabatic invaxiant for the nonconservative system of generalized classical mechanics is obtained, which can be called the Hojman adiabatic invaxiant. An example is also given to illustrate the application of the results.展开更多
The changes of radon content in underground water(water radon)recorded at about 200 stations in 32 earthquakes occurred in the mainland of China are studied in this paper. The result shows that the spatial distributio...The changes of radon content in underground water(water radon)recorded at about 200 stations in 32 earthquakes occurred in the mainland of China are studied in this paper. The result shows that the spatial distribution of short term and imminent anomalies of water radon before earthquake seems to be mainly related to the active master fault nearby the hypocenter of an earthquake and the earthquake generating mechanism. Finally, some understandings on the mechanism of the aomalies and the imminent earthquake prediction are set forth.展开更多
This paper focuses on a new symmetry of Hamiltonian and its conserved quantity for a system of generalized classical mechanics. The differential equations of motion of the system are established. The definition and th...This paper focuses on a new symmetry of Hamiltonian and its conserved quantity for a system of generalized classical mechanics. The differential equations of motion of the system are established. The definition and the criterion of the symmetry of Hamiltonian of the system are given. A conserved quantity directly derived from the symmetry of Hamiltonian of the generalized classical mechanical system is given. Since a Hamilton system is a special case of the generalized classical mechanics, the results above are equally applicable to the Hamilton system. The results of the paper are the generalization of a theorem known for the existing nonsingular equivalent Lagrangian. Finally, two examples are given to illustrate the application of the results.展开更多
In the present paper, three kinds of forms for Noether’s conservation laws of hol-onomic nonconservative dynamical systems in generalized mechanics are given.
The characteristics and generation mechanism of（Ti,Nb,V）（C,N） precipitates larger than 2 μm in Nb-containing H13 bar steel were studied. The results show that two types of（Ti,Nb,V）（C,N） phases exist—a Ti-V-r...The characteristics and generation mechanism of（Ti,Nb,V）（C,N） precipitates larger than 2 μm in Nb-containing H13 bar steel were studied. The results show that two types of（Ti,Nb,V）（C,N） phases exist—a Ti-V-rich one and an Nb-rich one—in the form of single or complex precipitates. The sizes of the single Ti-V-rich（Ti,Nb,V）（C,N） precipitates are mostly within 5 to 10 μm, whereas the sizes of the single Nb-rich precipitates are mostly 2–5 μm. The complex precipitates are larger and contain an inner Ti-V-rich layer and an outer Nb-rich layer. The compositional distribution of（Ti,Nb,V）（C,N） is concentrated. The average composition of the single Ti-V-rich phase is（Ti_（0.511）V_（0.356）Nb_（0.133））（CxNy）, whereas that for the single Nb-rich phase is（Ti_（0.061）V_（0.263）Nb_（0.676））（C_xN_y）. The calculation results based on the Scheil–Gulliver model in the Thermo-Calc software combining with the thermal stability experiments show that the large phases precipitate during the solidification process. With the development of solidification, the Ti-V-rich phase precipitates first and becomes homogeneous during the subsequent temperature reduction and heat treatment processes. The Nb-rich phase appears later.展开更多
In the present paper the Lie symmetrical non-Noether conserved quantity of the Poincaré Chetaev equations of a generalized classical mechanics under the general infinitesimal transformations of Lie groups is disc...In the present paper the Lie symmetrical non-Noether conserved quantity of the Poincaré Chetaev equations of a generalized classical mechanics under the general infinitesimal transformations of Lie groups is discussed. First, we establish the determining equations of Lie symmetry of the equations. Second, the Lie symmetrical non-Noether conserved quantity of the equations is deduced. Finally, an example is given to illustrate the application of the results.展开更多
In this paper, firstly, we get the Hojman exact invariants by Lie symmetry for an undisturbed generalized Raitzin equation of motion. Secondly, we study the perturbation to Lie symmetry of generalized Raitzin canonica...In this paper, firstly, we get the Hojman exact invariants by Lie symmetry for an undisturbed generalized Raitzin equation of motion. Secondly, we study the perturbation to Lie symmetry of generalized Raitzin canonical equation of motion and get Hojman adiabatic invariants. Lastly, an example is given to illustrate the application of the results.展开更多
Cavitation generation methods have been used in multifarious directions because of their diversity,and numerous studies and discussions have been conducted on cavitation generation methods.This study aims to explore t...Cavitation generation methods have been used in multifarious directions because of their diversity,and numerous studies and discussions have been conducted on cavitation generation methods.This study aims to explore the generating mechanism and evolution law of volume alternate cavitation(VAC).In the VAC,liquid water is placed in an airtight container with a variable volume.As the volume alternately changes,the liquid water inside the container continues to cavitate.Then,the mixture turbulence model and in-cylinder dynamic grid model are adopted to conduct computational fluid dynamics simulation of volume alternate cavitation.In the simulation,the cloud images at seven heights on the central axis are monitored,and the phenomenon and mechanism of height and eccentricity are analyzed in detail.By employing the cavitation flow visualization method,the generating mechanism and evolution law of cavitation are revealed.The synergistic effects of experiments and high-speed camera capturing confirm the correctness of the simulation results.In the experiment,the volume change stroke of the airtight container is set to 20 mm,the volume change frequency is 18 Hz,and the shooting frequency of the high-speed camera is set to 10000 FPS.The experimental results indicate that the position of the cavitation phenomenon has a reasonable law during the whole evolution cycle of the cavitation cloud.Also,the volume alternation cycle corresponds to the generation,development,and collapse stages of cavitation bubbles.展开更多
In this paper,the form invariance and the Lie symmetry of Lagrange's equations for nonconservativesystem in generalized classical mechanics under the infinitesimal transformations of group are studied,and the Noet...In this paper,the form invariance and the Lie symmetry of Lagrange's equations for nonconservativesystem in generalized classical mechanics under the infinitesimal transformations of group are studied,and the Noether'sconserved quantity,the new form conserved quantity,and the Hojman's conserved quantity of system are derived fromthem.Finally,an example is given to illustrate the application of the result.展开更多
In this paper, the Noether Lie symmetry and conserved quantities of generalized classical mechanical system are studied. The definition and the criterion of the Noether Lie symmetry for the system under the general in...In this paper, the Noether Lie symmetry and conserved quantities of generalized classical mechanical system are studied. The definition and the criterion of the Noether Lie symmetry for the system under the general infinitesimal transformations of groups are given. The Noether conserved quantity and the Hojman conserved quantity deduced from the Noether Lie symmetry are obtained. An example is given to illustrate the application of the results.展开更多
By introducing the quasi-symmetry of the infinitesimal transformation of the transformation group Gr, the Noether＇s theorem and the Noether＇s inverse theorem for generalized linear nonholonomic mechanical systems ar...By introducing the quasi-symmetry of the infinitesimal transformation of the transformation group Gr, the Noether＇s theorem and the Noether＇s inverse theorem for generalized linear nonholonomic mechanical systems are obtained in a generalized compound derivative space. An example is given to illustrate the application of the result.展开更多
A reliability-based analysis approach to mechanical error in path generating linkages is pre- sented . The reliability index is taken as a measure for the deviation of the actual path of a coupler point from the desir...A reliability-based analysis approach to mechanical error in path generating linkages is pre- sented . The reliability index is taken as a measure for the deviation of the actual path of a coupler point from the desired one. A reliability-based synthesis procedure of the mechanical error for path generating linkages to allocate optimal tolerances and clearances is developed. A four-bar path generating mechanism is considered for numerical illustration.展开更多
In this paper we consider that the momentum of a free particle motion withhigh-level speed presenting nonlinear effects may be expanded by using Laurent seriesand then obtain the complete expression of nonlinear and u...In this paper we consider that the momentum of a free particle motion withhigh-level speed presenting nonlinear effects may be expanded by using Laurent seriesand then obtain the complete expression of nonlinear and unsteady momentum. These nonlinear and unsieady phenoniena of high-level speed may further expand to the theory of kinematics and it may be determined by Fredholm's integral equation of the first kind. In addition, according to the nonlinear and unsteady momentum obtained the relations of the nonlinear mechanics equations .work and energy, mass and energymay be derived.Finaly .this paper also calculates those experimental results which done in particle physics for mu-mesons u±and fast neutrons n, these results are in agreement with data perfectly.展开更多
The human serotonin transporter(SERT)terminates neurotransmission by removing serotonin from the synaptic cleft,which is an essential process that plays an important role in depression.In addition to natural substrate...The human serotonin transporter(SERT)terminates neurotransmission by removing serotonin from the synaptic cleft,which is an essential process that plays an important role in depression.In addition to natural substrate serotonin,SERT is also the target of the abused drug cocaine and,clinically used antidepressants,escitalopram,and paroxetine.To date,few studies have attempted to investigate the unbinding mechanism underlying the orthosteric and allosteric modulation of SERT.In this article,the conserved property of the orthosteric and allosteric sites(S1 and S2)of SERT was revealed by combining the high resolutions of x-ray crystal structures and molecular dynamics(MD)simulations.The residues Tyr95 and Ser438 located within the S1 site,and Arg104 located within the S2 site in SERT illustrate conserved interactions(hydrogen bonds and hydrophobic interactions),as responses to selective serotonin reuptake inhibitors.Van der Waals interactions were keys to designing effective drugs inhibiting SERT and further,electrostatic interactions highlighted escitalopram as a potent antidepressant.We found that cocaine,escitalopram,and paroxetine,whether the S1 site or the S2 site,were more competitive.According to this potential of mean force(PMF)simulations,the new insights reveal the principles of competitive inhibitors that lengths of trails from central SERT to an opening were~18A for serotonin and~22 A for the above-mentioned three drugs.Furthermore,the distance between the natural substrate serotonin and cocaine(or escitalopram)at the allosteric site was~3A.Thus,it can be inferred that the potent antidepressants tended to bind at deeper positions of the S1 or the S2 site of SERT in comparison to the substrate.Continuing exploring the processes of unbinding four ligands against the two target pockets of SERT,this study observed a broad pathway in which serotonin,cocaine,escitalopram(at the S1 site),and paroxetine all were pulled out to an opening between MT1b and MT6a,which may be helpful to understand the dissociation mechanism of antidepressants.展开更多
A generalized scheme for the construction of coherent states in the context of position-dependent effective mass systems has been presented. This formalism is based on the ladder operators and associated algebra of th...A generalized scheme for the construction of coherent states in the context of position-dependent effective mass systems has been presented. This formalism is based on the ladder operators and associated algebra of the system which are obtained using the concepts of supersymmetric quantum mechanics and the property of shape invariance. In order to exemplify the general results and to analyze the properties of the coherent states, several examples have been considered.展开更多
Generalized parallel mechanisms with a configurable moving platform have become popular in the research field of parallel mechanism.This type of gripper mechanism can be applied to grasp large or heavy objects in diff...Generalized parallel mechanisms with a configurable moving platform have become popular in the research field of parallel mechanism.This type of gripper mechanism can be applied to grasp large or heavy objects in different environments that are dangerous and complex for humans.This study proposes a family of novel(5+1)degrees of freedom(three translations and two rotations plus an additional grasping motion)gripper mechanisms based on the generalized parallel mechanisms with a configurable moving platform.First,the configurable moving platform,which is a closed loop,is designed for grasping manipulation.The hybrid topological arrangement is determined to improve the stiffness of the manipulator and realize high load-to-weight ratios.A sufficient rule based on Lie group theory is proposed to synthesize the mechanism.TTie hybrid limb structure is also enumerated.A family of novel gripper mechanisms can be assembled through the hybrid limbs by satisfying the rule.Two examples of the gripper mechanisms with and without parallelogram pairs are shown in this study.A kinematic analysis of the example mechanism is presented.The workspace shows that the mechanism possesses high rotational capability.In addition,a stiffiiess analysis is performed.展开更多
基金Supported by National Natural Science Foundation of China(Grant No.52475280)Key Laboratory Project of the Key Program of the Natural Science Basic Research Program of Shaanxi Province of China(Grant No.2025SYS-SYSZD-105)+1 种基金Natural Science Foundation of Shaanxi Province of China(Grant No.2025JC-YBQN-505)China Postdoctoral Science Foundation(Grant No.2024M752510).
文摘As space equipment become larger in size and more flexible,generalized mechanisms are being widely used in space-deployable structures.Dynamic modeling of large-scale generalized space-deployable mechanisms is challenging owing to the coupling between the deformation of flexible links and rigid body motion.This study develops a dynamic modeling method for generalized mechanisms using the local frame of the SE(3)Lie group.The model represents both rigid and flexible links within a unified Lie group setting.The expressions for the velocities of rigid links and deformation of flexible links are derived using the Lie algebra framework.The nonuniqueness of the degrees of freedom of generalized kinematic pairs is considered,and the velocity fields of kinematic pairs in different situations are expressed.The equations of motion are derived using Hamilton’s principle.Because the velocities are expressed in the local frame,the mass matrix in the equation is constant,which yields a compact and unified expression for the dynamic equation.A Lie group generalized-αtime integration method is adopted to ensure numerical stability and efficiency in simulating multibody systems with large rotations and deformations.Two numerical examples are studied to demonstrate a formulation that reflects the motion responses under varying configurations and loading conditions.This study broadens the application of the local frame of the Lie group formulation in space mechanisms and provides a new concept for dynamic modeling of generalized mechanisms.
基金the Fund of Shanghai Keystone Subject (No.P1404)
文摘An automatic patch snatching system is described which has three machine cells including dividing equipment, tackling equipment and patch removing equipment. The electromechanical integration design of in-piece tackling system based on the concept of generalized mechanisms is introduced. The design of the dividing equipment, the design of micro-feeding machine equipped with micro-level pressure sensor, and the realizing of computer path for patch snatching are investigated.
基金Project supported by the Natural Science Foundation of High Education of Jiangsu Province, China （Grant No 04KJA130135）.
文摘The perturbations to symmetries and adiabatic invariants for nonconservative systems of generalized classical mechanics axe studied. The exact inwriant in the form of Hojman from a particular Lie symmetry for an undisturbed system of generalized mechanics is given. Based on the concept of high-order adiabatic invaxiant in generalized mechanics, the perturbation to Lie symmetry for the system under the action of small disturbance is investigated, and a new adiabatic invaxiant for the nonconservative system of generalized classical mechanics is obtained, which can be called the Hojman adiabatic invaxiant. An example is also given to illustrate the application of the results.
文摘The changes of radon content in underground water(water radon)recorded at about 200 stations in 32 earthquakes occurred in the mainland of China are studied in this paper. The result shows that the spatial distribution of short term and imminent anomalies of water radon before earthquake seems to be mainly related to the active master fault nearby the hypocenter of an earthquake and the earthquake generating mechanism. Finally, some understandings on the mechanism of the aomalies and the imminent earthquake prediction are set forth.
基金supported by the National Natural Science Foundation of China (Grant No. 10972151)
文摘This paper focuses on a new symmetry of Hamiltonian and its conserved quantity for a system of generalized classical mechanics. The differential equations of motion of the system are established. The definition and the criterion of the symmetry of Hamiltonian of the system are given. A conserved quantity directly derived from the symmetry of Hamiltonian of the generalized classical mechanical system is given. Since a Hamilton system is a special case of the generalized classical mechanics, the results above are equally applicable to the Hamilton system. The results of the paper are the generalization of a theorem known for the existing nonsingular equivalent Lagrangian. Finally, two examples are given to illustrate the application of the results.
文摘In the present paper, three kinds of forms for Noether’s conservation laws of hol-onomic nonconservative dynamical systems in generalized mechanics are given.
文摘The characteristics and generation mechanism of（Ti,Nb,V）（C,N） precipitates larger than 2 μm in Nb-containing H13 bar steel were studied. The results show that two types of（Ti,Nb,V）（C,N） phases exist—a Ti-V-rich one and an Nb-rich one—in the form of single or complex precipitates. The sizes of the single Ti-V-rich（Ti,Nb,V）（C,N） precipitates are mostly within 5 to 10 μm, whereas the sizes of the single Nb-rich precipitates are mostly 2–5 μm. The complex precipitates are larger and contain an inner Ti-V-rich layer and an outer Nb-rich layer. The compositional distribution of（Ti,Nb,V）（C,N） is concentrated. The average composition of the single Ti-V-rich phase is（Ti_（0.511）V_（0.356）Nb_（0.133））（CxNy）, whereas that for the single Nb-rich phase is（Ti_（0.061）V_（0.263）Nb_（0.676））（C_xN_y）. The calculation results based on the Scheil–Gulliver model in the Thermo-Calc software combining with the thermal stability experiments show that the large phases precipitate during the solidification process. With the development of solidification, the Ti-V-rich phase precipitates first and becomes homogeneous during the subsequent temperature reduction and heat treatment processes. The Nb-rich phase appears later.
文摘In the present paper the Lie symmetrical non-Noether conserved quantity of the Poincaré Chetaev equations of a generalized classical mechanics under the general infinitesimal transformations of Lie groups is discussed. First, we establish the determining equations of Lie symmetry of the equations. Second, the Lie symmetrical non-Noether conserved quantity of the equations is deduced. Finally, an example is given to illustrate the application of the results.
文摘In this paper, firstly, we get the Hojman exact invariants by Lie symmetry for an undisturbed generalized Raitzin equation of motion. Secondly, we study the perturbation to Lie symmetry of generalized Raitzin canonical equation of motion and get Hojman adiabatic invariants. Lastly, an example is given to illustrate the application of the results.
基金Supported by National Nature Science Foundation of China(Grant No.51575245)Jiangsu Provincial Key research and development program(Grant No.BE2015134)Zhenjiang Municipal Key Research and Development Project(Grant No.KZ2020001).
文摘Cavitation generation methods have been used in multifarious directions because of their diversity,and numerous studies and discussions have been conducted on cavitation generation methods.This study aims to explore the generating mechanism and evolution law of volume alternate cavitation(VAC).In the VAC,liquid water is placed in an airtight container with a variable volume.As the volume alternately changes,the liquid water inside the container continues to cavitate.Then,the mixture turbulence model and in-cylinder dynamic grid model are adopted to conduct computational fluid dynamics simulation of volume alternate cavitation.In the simulation,the cloud images at seven heights on the central axis are monitored,and the phenomenon and mechanism of height and eccentricity are analyzed in detail.By employing the cavitation flow visualization method,the generating mechanism and evolution law of cavitation are revealed.The synergistic effects of experiments and high-speed camera capturing confirm the correctness of the simulation results.In the experiment,the volume change stroke of the airtight container is set to 20 mm,the volume change frequency is 18 Hz,and the shooting frequency of the high-speed camera is set to 10000 FPS.The experimental results indicate that the position of the cavitation phenomenon has a reasonable law during the whole evolution cycle of the cavitation cloud.Also,the volume alternation cycle corresponds to the generation,development,and collapse stages of cavitation bubbles.
基金National Natural Science Foundation of China under Grant No.10272034the Doctoral Program Foundation of China
文摘In this paper,the form invariance and the Lie symmetry of Lagrange's equations for nonconservativesystem in generalized classical mechanics under the infinitesimal transformations of group are studied,and the Noether'sconserved quantity,the new form conserved quantity,and the Hojman's conserved quantity of system are derived fromthem.Finally,an example is given to illustrate the application of the result.
文摘In this paper, the Noether Lie symmetry and conserved quantities of generalized classical mechanical system are studied. The definition and the criterion of the Noether Lie symmetry for the system under the general infinitesimal transformations of groups are given. The Noether conserved quantity and the Hojman conserved quantity deduced from the Noether Lie symmetry are obtained. An example is given to illustrate the application of the results.
基金Project supported by the Natural Science Foundation of Weifang University,China(Grant No.2008Z03)
文摘By introducing the quasi-symmetry of the infinitesimal transformation of the transformation group Gr, the Noether＇s theorem and the Noether＇s inverse theorem for generalized linear nonholonomic mechanical systems are obtained in a generalized compound derivative space. An example is given to illustrate the application of the result.
文摘A reliability-based analysis approach to mechanical error in path generating linkages is pre- sented . The reliability index is taken as a measure for the deviation of the actual path of a coupler point from the desired one. A reliability-based synthesis procedure of the mechanical error for path generating linkages to allocate optimal tolerances and clearances is developed. A four-bar path generating mechanism is considered for numerical illustration.
文摘In this paper we consider that the momentum of a free particle motion withhigh-level speed presenting nonlinear effects may be expanded by using Laurent seriesand then obtain the complete expression of nonlinear and unsteady momentum. These nonlinear and unsieady phenoniena of high-level speed may further expand to the theory of kinematics and it may be determined by Fredholm's integral equation of the first kind. In addition, according to the nonlinear and unsteady momentum obtained the relations of the nonlinear mechanics equations .work and energy, mass and energymay be derived.Finaly .this paper also calculates those experimental results which done in particle physics for mu-mesons u±and fast neutrons n, these results are in agreement with data perfectly.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11904036 and 12175081)Fundamental Research Funds for the Central Universities(Grant No.CCNU22QNOO4)。
文摘The human serotonin transporter(SERT)terminates neurotransmission by removing serotonin from the synaptic cleft,which is an essential process that plays an important role in depression.In addition to natural substrate serotonin,SERT is also the target of the abused drug cocaine and,clinically used antidepressants,escitalopram,and paroxetine.To date,few studies have attempted to investigate the unbinding mechanism underlying the orthosteric and allosteric modulation of SERT.In this article,the conserved property of the orthosteric and allosteric sites(S1 and S2)of SERT was revealed by combining the high resolutions of x-ray crystal structures and molecular dynamics(MD)simulations.The residues Tyr95 and Ser438 located within the S1 site,and Arg104 located within the S2 site in SERT illustrate conserved interactions(hydrogen bonds and hydrophobic interactions),as responses to selective serotonin reuptake inhibitors.Van der Waals interactions were keys to designing effective drugs inhibiting SERT and further,electrostatic interactions highlighted escitalopram as a potent antidepressant.We found that cocaine,escitalopram,and paroxetine,whether the S1 site or the S2 site,were more competitive.According to this potential of mean force(PMF)simulations,the new insights reveal the principles of competitive inhibitors that lengths of trails from central SERT to an opening were~18A for serotonin and~22 A for the above-mentioned three drugs.Furthermore,the distance between the natural substrate serotonin and cocaine(or escitalopram)at the allosteric site was~3A.Thus,it can be inferred that the potent antidepressants tended to bind at deeper positions of the S1 or the S2 site of SERT in comparison to the substrate.Continuing exploring the processes of unbinding four ligands against the two target pockets of SERT,this study observed a broad pathway in which serotonin,cocaine,escitalopram(at the S1 site),and paroxetine all were pulled out to an opening between MT1b and MT6a,which may be helpful to understand the dissociation mechanism of antidepressants.
文摘A generalized scheme for the construction of coherent states in the context of position-dependent effective mass systems has been presented. This formalism is based on the ladder operators and associated algebra of the system which are obtained using the concepts of supersymmetric quantum mechanics and the property of shape invariance. In order to exemplify the general results and to analyze the properties of the coherent states, several examples have been considered.
基金This research work was supported by the Fundamental Research Funds for the Central Universities,China(Grant No.2020YJS153)the National Natural Science Foundation of China(Grant No.51975039).
文摘Generalized parallel mechanisms with a configurable moving platform have become popular in the research field of parallel mechanism.This type of gripper mechanism can be applied to grasp large or heavy objects in different environments that are dangerous and complex for humans.This study proposes a family of novel(5+1)degrees of freedom(three translations and two rotations plus an additional grasping motion)gripper mechanisms based on the generalized parallel mechanisms with a configurable moving platform.First,the configurable moving platform,which is a closed loop,is designed for grasping manipulation.The hybrid topological arrangement is determined to improve the stiffness of the manipulator and realize high load-to-weight ratios.A sufficient rule based on Lie group theory is proposed to synthesize the mechanism.TTie hybrid limb structure is also enumerated.A family of novel gripper mechanisms can be assembled through the hybrid limbs by satisfying the rule.Two examples of the gripper mechanisms with and without parallelogram pairs are shown in this study.A kinematic analysis of the example mechanism is presented.The workspace shows that the mechanism possesses high rotational capability.In addition,a stiffiiess analysis is performed.
