An improved half-vehicle model has been proposed for active suspension control systems, in contrast to existing models, it allows to explore the nature of the effect of vehicle speed changes by introducing a state vec...An improved half-vehicle model has been proposed for active suspension control systems, in contrast to existing models, it allows to explore the nature of the effect of vehicle speed changes by introducing a state vector of vehicle pitch angle. Three control strategies of linear quadratic control (LQ), improved LQ (ILQ) and wheelbase preview LQ (WLQ) have been implemented into the proposed model. ILQ has integrated an additional control parameter into LQ by concerning the correlation between acceleration values and their corresponding pitch angles. Simulation results have showed the effectiveness of the proposed model in terms of LQ, ILQ and WLQ control strategies.展开更多
We use the Bethe’s ansatz method to study the entanglement of spinons in the quantum phase transition of half integer spin one-dimensional magnetic chains known as quantum wires. We calculate the entanglement in the ...We use the Bethe’s ansatz method to study the entanglement of spinons in the quantum phase transition of half integer spin one-dimensional magnetic chains known as quantum wires. We calculate the entanglement in the limit of the number of particles . We obtain an abrupt change in the entanglement next the quantum phase transition point of the anisotropy parameter ?from the gapped phase ?to gapless phase .展开更多
This paper investigates the problem of controlling half-vehicle semi-active suspension system involving a magnetorheological(MR)damper.This features a hysteretic behavior that is presently captured through the nonline...This paper investigates the problem of controlling half-vehicle semi-active suspension system involving a magnetorheological(MR)damper.This features a hysteretic behavior that is presently captured through the nonlinear Bouc-Wen model.The control objective is to regulate well the heave and the pitch motions of the chassis despite the road irregularities.The difficulty of the control problem lies in the nonlinearity of the system model,the uncertainty of some of its parameters,and the inaccessibility to measurements of the hysteresis internal state variables.Using Lyapunov control design tools,we design two observers to get online estimates of the hysteresis internal states and a stabilizing adaptive state-feedback regulator.The whole adaptive controller is formally shown to meet the desired control objectives.This theoretical result is confirmed by several simulations demonstrating the supremacy of the latter compared to the skyhook control and passive suspension.展开更多
This paper presents a modified half-sine-squared load model of the jumping impulses for a single person. The model is based on a database of 22,921 experimentally measured single jumping load cycles from 100 test subj...This paper presents a modified half-sine-squared load model of the jumping impulses for a single person. The model is based on a database of 22,921 experimentally measured single jumping load cycles from 100 test subjects. Threedimensional motion capture technology in conjunction with force plates was employed in the experiment to record jumping loads. The variation range and probability distribution of the controlling parameters for the load model such as the impact factor, jumping frequency and contact ratio, are discussed using the experimental data. Correlation relationships between the three parameters are investigated. The contact ratio and jumping frequency are identified as independent model parameters, and an empirical frequency-dependent function is derived for the impact factor. The feasibility of the proposed load model is established by comparing the simulated load curves with measured ones, and by comparing the acceleration responses of a single-degree-of-freedom system to the simulated and measured jumping loads. The results show that a realistic individual jumping load can be generated by the proposed method. This can then be used to assess the dynamic response of assembly structures.展开更多
The formation mechanism of the contact angle and the sliding angle for a liquid drop on a solid surface plays an important role in producing hydrophobic surfaces. A new half soakage model is established in this paper ...The formation mechanism of the contact angle and the sliding angle for a liquid drop on a solid surface plays an important role in producing hydrophobic surfaces. A new half soakage model is established in this paper as a substitute for Wenzel (complete soakage) and Cassie (no soakage) models. The model is suited to many solid surfaces, whether they are hydrophilic or hydrophobic, or even superhydrophobic. Based on the half soakage model, we analyse two surfaces resembling lotus, i.e. taper-like surface and corona-like surface. Furthermore, this new model is used to establish a quantitative relationship between the sliding angle and the parameters of surface morphology.展开更多
Based on the newest experimentally extracted nuclear density distributions for double-magic nucleus208Pb(Tarbert et al. in Phys Rev Lett 112:242502, 2014),the sensitivity of α-decay half-life to nuclear skin thicknes...Based on the newest experimentally extracted nuclear density distributions for double-magic nucleus208Pb(Tarbert et al. in Phys Rev Lett 112:242502, 2014),the sensitivity of α-decay half-life to nuclear skin thickness is explored in the vicinity of the shell closure region around208 Pb, i.e., isotopes of Z ? 82 and isotones of N ? 126.With the two-parameter Fermi(2PF) density distributions and an analytically derived formula, the α-decay half-life is found to be closely related to the magnitude of nuclear skin thickness. For a decays to the Z ? 82 isotopes, the α-decay half-life is found to decrease with the increasing neutron skin thickness, while the opposite behavior is found for a decays to the N ? 126 isotones. Therefore, it could be a possible way to extract the nuclear skin thickness from measured α-decay half-lives.展开更多
A new version of the generalized density-dependent cluster model (GDDCM) is developed to describe an α particle tunneling through a deformed potential barrier. The microscopic deformed potential is numerically cons...A new version of the generalized density-dependent cluster model (GDDCM) is developed to describe an α particle tunneling through a deformed potential barrier. The microscopic deformed potential is numerically constructed in the double-folding model using the multipole ex- pansion method. The decay width of an α-cluster state is evaluated using the integral of the quasi-bound state wave function, the scattering state wave function, and the difference of poten- tials. We perform a systematic calculation of α-decay half-lives for favored transitions in even-even nuclei ranging from Z=52 to Z=104. The calculated half-lives are in good agreement with the experimental values. The relation between nuclear deformations and α-decay half-lives is also discussed in details.展开更多
The quantitative structure-property relationship(QSPR) of anabolic androgenic steroids was studied on the half-wave reduction potential(E1/2) using quantum and physico-chemical molecular descriptors. The descriptors w...The quantitative structure-property relationship(QSPR) of anabolic androgenic steroids was studied on the half-wave reduction potential(E1/2) using quantum and physico-chemical molecular descriptors. The descriptors were calculated by semi-empirical calculations. Models were established using partial least square(PLS) regression and back-propagation artificial neural network(BP-ANN). The QSPR results indicate that the descriptors of these derivatives have significant relationship with half-wave reduction potential. The stability and prediction ability of these models were validated using leave-one-out cross-validation and external test set.展开更多
In this paper,by considering the electrons in different external environments,including neutral atoms,a metal,and an extremely strong magnetic-field environment,the screened a-decay half-lives of the a emitters with p...In this paper,by considering the electrons in different external environments,including neutral atoms,a metal,and an extremely strong magnetic-field environment,the screened a-decay half-lives of the a emitters with proton number Z = 52–105 are systematically calculated.In the external environment,the decay energy and the interaction potential between a particle and daughter nucleus are both changed due to the electron screening effect and their variations are both very important for the electron screening effect.Besides,the electron screening effect is found to be closely related to the decay energy and its proton number.展开更多
Dynamic modeling was carried on by combining the dynamic of machinery with composite triology, and the critical condition in which the ways would not produce composite-friction self-excited vibration was obtained. The...Dynamic modeling was carried on by combining the dynamic of machinery with composite triology, and the critical condition in which the ways would not produce composite-friction self-excited vibration was obtained. The movement regularity and characteristic of the airflow in exhaust gas slit were analyzed, and the relationship between pressure lost and geometry parameters of exhaust gas slit was obtained. A dynamic model and a mathematical model were established for pneumatic half-floating slide ways by combining the dynamics of machinery with hydrokinetics. The objective function for the optimization of slide ways was established based on the fuzzy optimization theory. The membership function of fuzzy constraint was deduced, the fuzzy constraint limit was established by amplification coefficient method, and the optimal value was resolved by the multilevel fuzzy comprehensive evaluation method. By combining the internal penalty function method with the variable metric method, the fuzzy optimization design program of ways was designed based on the Matlab platform. The validation was carried on by an example, and ideal results of fuzzy optimization design of slide ways were obtained.展开更多
新能源汽车转向驱动桥半轴采用空心设计,与燃油汽车的结构形式有很大区别,针对电动汽车转向驱动桥空心半轴的最大等效应力与设计变量呈隐式复杂非线性关系的可靠度分析难题,文中通过将Kriging模型与蒙特卡洛(Monte Carlo Simulation,MCS...新能源汽车转向驱动桥半轴采用空心设计,与燃油汽车的结构形式有很大区别,针对电动汽车转向驱动桥空心半轴的最大等效应力与设计变量呈隐式复杂非线性关系的可靠度分析难题,文中通过将Kriging模型与蒙特卡洛(Monte Carlo Simulation,MCS)法相结合,提出了基于AK-MCS(Active Learning Kriging-Monte Carlo Simulation)法的新能源电动汽车转向驱动桥空心半轴可靠度分析方法。首先,采用Kriging代理模型构建新能源电动汽车转向驱动桥空心半轴的最大等效应力的初始代理模型;其次,通过Kriging提供的学习函数和收敛准则逐步增加样本点,从而对初始最大等效应力的Kriging模型进行更新;最后,对更新后的Kriging代理模型计算新能源电动汽车转向驱动桥空心半轴的可靠度。结果表明:与MCS方法相比,基于AK-MCS方法的可靠度分析在时间上缩短2000余倍;与Kriging+MCS方法相比,基于AK-MCS方法的可靠度分析误差减小了50%。由此验证了基于AK-MCS方法空心半轴可靠度分析的高效性和准确性,为电动汽车转向驱动桥空心半轴可靠性的研究提供了理论依据,具有一定的工程意义。展开更多
文摘An improved half-vehicle model has been proposed for active suspension control systems, in contrast to existing models, it allows to explore the nature of the effect of vehicle speed changes by introducing a state vector of vehicle pitch angle. Three control strategies of linear quadratic control (LQ), improved LQ (ILQ) and wheelbase preview LQ (WLQ) have been implemented into the proposed model. ILQ has integrated an additional control parameter into LQ by concerning the correlation between acceleration values and their corresponding pitch angles. Simulation results have showed the effectiveness of the proposed model in terms of LQ, ILQ and WLQ control strategies.
文摘We use the Bethe’s ansatz method to study the entanglement of spinons in the quantum phase transition of half integer spin one-dimensional magnetic chains known as quantum wires. We calculate the entanglement in the limit of the number of particles . We obtain an abrupt change in the entanglement next the quantum phase transition point of the anisotropy parameter ?from the gapped phase ?to gapless phase .
文摘This paper investigates the problem of controlling half-vehicle semi-active suspension system involving a magnetorheological(MR)damper.This features a hysteretic behavior that is presently captured through the nonlinear Bouc-Wen model.The control objective is to regulate well the heave and the pitch motions of the chassis despite the road irregularities.The difficulty of the control problem lies in the nonlinearity of the system model,the uncertainty of some of its parameters,and the inaccessibility to measurements of the hysteresis internal state variables.Using Lyapunov control design tools,we design two observers to get online estimates of the hysteresis internal states and a stabilizing adaptive state-feedback regulator.The whole adaptive controller is formally shown to meet the desired control objectives.This theoretical result is confirmed by several simulations demonstrating the supremacy of the latter compared to the skyhook control and passive suspension.
基金the National Natural Science Foundation of China under Grant Nos.51178338 and 51478346State Key Laboratory of Disaster Reduction in Civil Engineering under Grant No.SLDRCE14-B-16
文摘This paper presents a modified half-sine-squared load model of the jumping impulses for a single person. The model is based on a database of 22,921 experimentally measured single jumping load cycles from 100 test subjects. Threedimensional motion capture technology in conjunction with force plates was employed in the experiment to record jumping loads. The variation range and probability distribution of the controlling parameters for the load model such as the impact factor, jumping frequency and contact ratio, are discussed using the experimental data. Correlation relationships between the three parameters are investigated. The contact ratio and jumping frequency are identified as independent model parameters, and an empirical frequency-dependent function is derived for the impact factor. The feasibility of the proposed load model is established by comparing the simulated load curves with measured ones, and by comparing the acceleration responses of a single-degree-of-freedom system to the simulated and measured jumping loads. The results show that a realistic individual jumping load can be generated by the proposed method. This can then be used to assess the dynamic response of assembly structures.
基金Project supported by the National Basic Research Program of China (Grant No. 2006CB302900)the National Natural Science Foundation of China (Grant No. 50872129)
文摘The formation mechanism of the contact angle and the sliding angle for a liquid drop on a solid surface plays an important role in producing hydrophobic surfaces. A new half soakage model is established in this paper as a substitute for Wenzel (complete soakage) and Cassie (no soakage) models. The model is suited to many solid surfaces, whether they are hydrophilic or hydrophobic, or even superhydrophobic. Based on the half soakage model, we analyse two surfaces resembling lotus, i.e. taper-like surface and corona-like surface. Furthermore, this new model is used to establish a quantitative relationship between the sliding angle and the parameters of surface morphology.
基金supported by the National Natural Science Foundation of China(Nos.11175085,11235001,11375086,and 11120101005)the 973 Program of China(No.2013CB834400)+1 种基金the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Open Project Program of the State Key Laboratory of Theoretical Physics,Institute of Theoretical Physics,Chinese Academy of Sciences,China(No.Y5KF141CJ1)
文摘Based on the newest experimentally extracted nuclear density distributions for double-magic nucleus208Pb(Tarbert et al. in Phys Rev Lett 112:242502, 2014),the sensitivity of α-decay half-life to nuclear skin thickness is explored in the vicinity of the shell closure region around208 Pb, i.e., isotopes of Z ? 82 and isotones of N ? 126.With the two-parameter Fermi(2PF) density distributions and an analytically derived formula, the α-decay half-life is found to be closely related to the magnitude of nuclear skin thickness. For a decays to the Z ? 82 isotopes, the α-decay half-life is found to decrease with the increasing neutron skin thickness, while the opposite behavior is found for a decays to the N ? 126 isotones. Therefore, it could be a possible way to extract the nuclear skin thickness from measured α-decay half-lives.
基金supported by National Natural Science Foundation of China(Nos.10535010,10675090,10775068,10735010,10975072,11035001)973 National Major State Basic Research and Development of China(Nos.2007CB815004,2010CB327803)+1 种基金CAS Knowledge Innovation Project(No.KJCX2-SW-N02)Research Fund of Doctoral Point(RFDP) of China(Nos.20070284016,20100091110028)
文摘A new version of the generalized density-dependent cluster model (GDDCM) is developed to describe an α particle tunneling through a deformed potential barrier. The microscopic deformed potential is numerically constructed in the double-folding model using the multipole ex- pansion method. The decay width of an α-cluster state is evaluated using the integral of the quasi-bound state wave function, the scattering state wave function, and the difference of poten- tials. We perform a systematic calculation of α-decay half-lives for favored transitions in even-even nuclei ranging from Z=52 to Z=104. The calculated half-lives are in good agreement with the experimental values. The relation between nuclear deformations and α-decay half-lives is also discussed in details.
基金Project supported by the Postdoctoral Science Foundation of Central South University,ChinaProject(2015SK20823)supported by Science and Technology Project of Hunan Province,China+2 种基金Project(15A001)supported by Scientific Research Fund of Hunan Provincial Education Department,ChinaProject(CX2015B372)supported by Hunan Provincial Innovation Foundation for Postgraduate,ChinaProject supported by Innovation Experiment Program for University Students of Changsha University of Science and Technology,China
文摘The quantitative structure-property relationship(QSPR) of anabolic androgenic steroids was studied on the half-wave reduction potential(E1/2) using quantum and physico-chemical molecular descriptors. The descriptors were calculated by semi-empirical calculations. Models were established using partial least square(PLS) regression and back-propagation artificial neural network(BP-ANN). The QSPR results indicate that the descriptors of these derivatives have significant relationship with half-wave reduction potential. The stability and prediction ability of these models were validated using leave-one-out cross-validation and external test set.
基金supported by the National Natural Science Foundation of China(Nos.11175085,11235001,11375086,and 11120101005)by the 973 Program of China(No.2013CB834400)+1 种基金by the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)by the Open Project Program of the State Key Laboratory of Theoretical Physics,Institute of Theoretical Physics,Chinese Academy of Sciences,China(No.Y5KF141CJ1)
文摘In this paper,by considering the electrons in different external environments,including neutral atoms,a metal,and an extremely strong magnetic-field environment,the screened a-decay half-lives of the a emitters with proton number Z = 52–105 are systematically calculated.In the external environment,the decay energy and the interaction potential between a particle and daughter nucleus are both changed due to the electron screening effect and their variations are both very important for the electron screening effect.Besides,the electron screening effect is found to be closely related to the decay energy and its proton number.
基金Project(50775194) supported by the National Natural Science Foundation of China
文摘Dynamic modeling was carried on by combining the dynamic of machinery with composite triology, and the critical condition in which the ways would not produce composite-friction self-excited vibration was obtained. The movement regularity and characteristic of the airflow in exhaust gas slit were analyzed, and the relationship between pressure lost and geometry parameters of exhaust gas slit was obtained. A dynamic model and a mathematical model were established for pneumatic half-floating slide ways by combining the dynamics of machinery with hydrokinetics. The objective function for the optimization of slide ways was established based on the fuzzy optimization theory. The membership function of fuzzy constraint was deduced, the fuzzy constraint limit was established by amplification coefficient method, and the optimal value was resolved by the multilevel fuzzy comprehensive evaluation method. By combining the internal penalty function method with the variable metric method, the fuzzy optimization design program of ways was designed based on the Matlab platform. The validation was carried on by an example, and ideal results of fuzzy optimization design of slide ways were obtained.
文摘新能源汽车转向驱动桥半轴采用空心设计,与燃油汽车的结构形式有很大区别,针对电动汽车转向驱动桥空心半轴的最大等效应力与设计变量呈隐式复杂非线性关系的可靠度分析难题,文中通过将Kriging模型与蒙特卡洛(Monte Carlo Simulation,MCS)法相结合,提出了基于AK-MCS(Active Learning Kriging-Monte Carlo Simulation)法的新能源电动汽车转向驱动桥空心半轴可靠度分析方法。首先,采用Kriging代理模型构建新能源电动汽车转向驱动桥空心半轴的最大等效应力的初始代理模型;其次,通过Kriging提供的学习函数和收敛准则逐步增加样本点,从而对初始最大等效应力的Kriging模型进行更新;最后,对更新后的Kriging代理模型计算新能源电动汽车转向驱动桥空心半轴的可靠度。结果表明:与MCS方法相比,基于AK-MCS方法的可靠度分析在时间上缩短2000余倍;与Kriging+MCS方法相比,基于AK-MCS方法的可靠度分析误差减小了50%。由此验证了基于AK-MCS方法空心半轴可靠度分析的高效性和准确性,为电动汽车转向驱动桥空心半轴可靠性的研究提供了理论依据,具有一定的工程意义。