Maintaining contact stability is crucial when the aerial manipulator interacts with the surrounding environment. In this paper, a novel output feedback framework based on a characteristic model is proposed to improve ...Maintaining contact stability is crucial when the aerial manipulator interacts with the surrounding environment. In this paper, a novel output feedback framework based on a characteristic model is proposed to improve the contact stability of the aerial manipulator. First, only position measurements of the aerial manipulator are introduced to design the practical finite-time command filter-based force observer. Second, an attitude control architecture including characteristic modeling and controller design is presented. In the modeling part, input-output data is utilized to build the characteristic model with fewer parameters and a simpler structure than the traditional dynamic model. Different from conventional control methods, fewer feedback values,namely only angle information, are required for designing the controller in the controller part. In addition, the convergence of force estimation and the stability of the attitude control system are proved by the Lyapunov analysis. Numerical simulation comparisons are conducted to validate the effectiveness of the attitude controller and force observer. The comparative results demonstrate that the tracking error of x and θ channels decreases at least 10.62% and 10.53% under disturbances and the force estimation precision increases at least 45.19% in the different environmental stiffness. Finally, physical flight experiments are conducted to validate the effectiveness of the proposed framework by a self-built aerial manipulator platform.展开更多
The stabilities of the complexes of three pyridine-like ligands with M(II)(ATP)^(2-) and M(II)(M=Ni,Co)were studied by spectrophotometry and by comparing the stability constants of the ternary complexes with these of ...The stabilities of the complexes of three pyridine-like ligands with M(II)(ATP)^(2-) and M(II)(M=Ni,Co)were studied by spectrophotometry and by comparing the stability constants of the ternary complexes with these of the binary complexes.A stacking interaction between the pyridine ring and the purine ring of ATP is indicated.The general existence of the stacking interaction encourages us to interpret the antitumor mechanism of a new class of antitumor drugs.展开更多
This paper analyses the modal interactions in the nonlinear, size-dependent dynamics of geometrically imperfect microplates. Based on the modified couple stress theory,the equations of motion for the in-plane and out-...This paper analyses the modal interactions in the nonlinear, size-dependent dynamics of geometrically imperfect microplates. Based on the modified couple stress theory,the equations of motion for the in-plane and out-of-plane motions are obtained employing the von Kármán plate theory as well as Kirchhoff＇s hypotheses by means of the Lagrange equations. The equations of motions are solved using the pseudo-arclength continuation technique and direct timeintegration method. The system parameters are tuned to the values associated with modal interactions, and then nonlinear resonant responses and energy transfer are analysed.Nonlinear motion characteristics are shown in the form of frequency-response and force-response curves, time histories, phase-plane portraits, and fast Fourier transforms.展开更多
With the increasing number of detected exoplanet samples, the statistical properties of planetary systems have become much clearer. In this review, we sum- marize the major statistical results that have been revealed ...With the increasing number of detected exoplanet samples, the statistical properties of planetary systems have become much clearer. In this review, we sum- marize the major statistical results that have been revealed mainly by radial velocity and transiting observations, and try to interpret them within the scope of the classical core-accretion scenario of planet formation, especially in the formation of different orbital architectures for planetary systems around main sequence stars. Based on the different possible formation routes for different planet systems, we tentatively classify them into three major catalogs： hot Jupiter systems, standard systems and distant giant planet systems. The standard systems can be further categorized into three sub-types under different circumstances： solar-like systems, hot Super-Earth systems, and sub- giant planet systems. We also review the theory of planet detection and formation in binary systems as well as planets in star clusters.展开更多
With the advancement of energy transition,residential photovoltaic(PV)systems face intermittency challenges that impact grid stability.While battery integration enhances resilience,existing approaches exhibit critical...With the advancement of energy transition,residential photovoltaic(PV)systems face intermittency challenges that impact grid stability.While battery integration enhances resilience,existing approaches exhibit critical gaps:(1)underdeveloped hybrid modeling frameworks balancing physical interpretability and data-driven accuracy;(2)reinforcement learning(RL)strategies prioritizing economic gains over grid stability,risking localized fluctuations;and(3)performance evaluations lacking systematic assessment across varying PV-battery capacities.To bridge these gaps,this study proposes a hybrid framework combining physical energy flow constraints with XGBoost-based machine learning for robust forecasting.Two optimization strategies,proximal policy optimization(PPO)and rule-based control(RBC),are developed for charge-discharge scheduling,explicitly incorporating grid stability metrics.Multi-scenario analysis evaluates performance under varying capacities and initial states of charge(SOC).Results demonstrate the hybrid model’s superiority over physics-based benchmarks,significantly improving prediction accuracy,with R2 increasing from 0.70 to 0.95 for SOC and from 0.83 to 0.98 for grid power.Both PPO and RBC enhance efficiency and stability versus baseline:the energy self-sufficiency rate rises from 10.6%to 79.3%(PPO)and 82.4%(RBC),while grid power fluctuations decrease from 2.6 kWh to 1.66 kWh(PPO)and 1.38 kWh(RBC).Crucially,RBC achieves higher stability and interpretability near boundaries,whereas PPO excels in long-term optimization but exhibits boundary-condition sensitivity.Results further reveal that PV-battery capacity and initial SOC influence strategy performance.This study establishes a structured technical pathway encompassing hybrid forecasting model development,stability-oriented optimization design,and scenario-based performance evaluation,providing an integrated solution to enhance grid resilience and energy autonomy in residential PV-battery systems.展开更多
Two examples of the use of vortex control to reduce noise and enhance the stable operating range of a centrifugal compressor are presented in this paper.In the case of high-flow operation of a centrifugal compressor w...Two examples of the use of vortex control to reduce noise and enhance the stable operating range of a centrifugal compressor are presented in this paper.In the case of high-flow operation of a centrifugal compressor with a vaned diffuser,a discrete frequency noise induced by interaction between the impeller-discharge flow and the diffuser vane,which appears most notably in the power spectra of the radiated noise,can be reduced using a tapered diffuser vane(TDV) without affecting the performance of the compressor.Twin longitudinal vortices produced by leakage flow passing through the tapered portion of the diffuser vane induce secondary flow in the direction of the blade surface and prevent flow separation from the leading edge of the diffuser.The use of a TDV can effectively reduce both the discrete frequency noise generated by the interaction between the impeller-discharge flow and the diffuser surface and the broadband turbulent noise component.In the case of low-flow operation,a leading-edge vortex(LEV) that forms on the shroud side of the suction surface near the leading edge of the diffuser increases significantly in size and blocks flow in the diffuser passage.The formation of an LEV may adversely affect the performance of the compressor and may cause the diffuser to stall.Using a one-side tapered diffuser vane to suppress the evolution of an LEV,the stable operating range of the compressor can be increased by more than 12 percent,and the pressure-rise characteristics of the compressor can be improved.The results of a supplementary examination of the structure and unsteady behavior of LEVs,conducted by means of detailed numerical simulations,are also presented.展开更多
At Shanghai Jiao Tong University（SJTU） we have established a research laboratory for advanced acceleration research based on high-power lasers and plasma technologies. In a primary experiment based on the laser wake...At Shanghai Jiao Tong University（SJTU） we have established a research laboratory for advanced acceleration research based on high-power lasers and plasma technologies. In a primary experiment based on the laser wakefield acceleration（LWFA） scheme, multi-hundred Me V electron beams of reasonable quality are generated using 20–40 TW, 30 femtosecond laser pulses interacting independently with helium, neon, nitrogen and argon gas jet targets. The laser-plasma interaction conditions are optimized for stabilizing the electron beam generation from each type of gas. The electron beam pointing angle stability and divergence angle as well as the energy spectra from each gas jet are measured and compared.展开更多
基金support partially by the Pre-research Task of State Key Laboratory of Robotics and Systems (HIT) (Grant No. SKLRS202402B)the National Natural Science Foundation of China (Grant No. 62273122)the Heilongjiang Natural Science Foundation (Grant No. YQ2023F009)。
文摘Maintaining contact stability is crucial when the aerial manipulator interacts with the surrounding environment. In this paper, a novel output feedback framework based on a characteristic model is proposed to improve the contact stability of the aerial manipulator. First, only position measurements of the aerial manipulator are introduced to design the practical finite-time command filter-based force observer. Second, an attitude control architecture including characteristic modeling and controller design is presented. In the modeling part, input-output data is utilized to build the characteristic model with fewer parameters and a simpler structure than the traditional dynamic model. Different from conventional control methods, fewer feedback values,namely only angle information, are required for designing the controller in the controller part. In addition, the convergence of force estimation and the stability of the attitude control system are proved by the Lyapunov analysis. Numerical simulation comparisons are conducted to validate the effectiveness of the attitude controller and force observer. The comparative results demonstrate that the tracking error of x and θ channels decreases at least 10.62% and 10.53% under disturbances and the force estimation precision increases at least 45.19% in the different environmental stiffness. Finally, physical flight experiments are conducted to validate the effectiveness of the proposed framework by a self-built aerial manipulator platform.
基金Supported by the National Natural Science Foundation of Chinathe Doctoral Program Foundation of Institution of High Education the Research Foundation of State Key Laboratory of Coordination Chemistry,Nanjing University.
文摘The stabilities of the complexes of three pyridine-like ligands with M(II)(ATP)^(2-) and M(II)(M=Ni,Co)were studied by spectrophotometry and by comparing the stability constants of the ternary complexes with these of the binary complexes.A stacking interaction between the pyridine ring and the purine ring of ATP is indicated.The general existence of the stacking interaction encourages us to interpret the antitumor mechanism of a new class of antitumor drugs.
文摘This paper analyses the modal interactions in the nonlinear, size-dependent dynamics of geometrically imperfect microplates. Based on the modified couple stress theory,the equations of motion for the in-plane and out-of-plane motions are obtained employing the von Kármán plate theory as well as Kirchhoff＇s hypotheses by means of the Lagrange equations. The equations of motions are solved using the pseudo-arclength continuation technique and direct timeintegration method. The system parameters are tuned to the values associated with modal interactions, and then nonlinear resonant responses and energy transfer are analysed.Nonlinear motion characteristics are shown in the form of frequency-response and force-response curves, time histories, phase-plane portraits, and fast Fourier transforms.
基金supported by the National Natural Science Foundation of China (Nos. 10833001, 10925313, 11078001 and 11003010)Fundamental Research Funds for the Central Universities (No. 1112020102)the Research Fund for the Doctoral Program of Higher Education of China (Nos. 20090091110002 and 20090091120025)
文摘With the increasing number of detected exoplanet samples, the statistical properties of planetary systems have become much clearer. In this review, we sum- marize the major statistical results that have been revealed mainly by radial velocity and transiting observations, and try to interpret them within the scope of the classical core-accretion scenario of planet formation, especially in the formation of different orbital architectures for planetary systems around main sequence stars. Based on the different possible formation routes for different planet systems, we tentatively classify them into three major catalogs： hot Jupiter systems, standard systems and distant giant planet systems. The standard systems can be further categorized into three sub-types under different circumstances： solar-like systems, hot Super-Earth systems, and sub- giant planet systems. We also review the theory of planet detection and formation in binary systems as well as planets in star clusters.
文摘With the advancement of energy transition,residential photovoltaic(PV)systems face intermittency challenges that impact grid stability.While battery integration enhances resilience,existing approaches exhibit critical gaps:(1)underdeveloped hybrid modeling frameworks balancing physical interpretability and data-driven accuracy;(2)reinforcement learning(RL)strategies prioritizing economic gains over grid stability,risking localized fluctuations;and(3)performance evaluations lacking systematic assessment across varying PV-battery capacities.To bridge these gaps,this study proposes a hybrid framework combining physical energy flow constraints with XGBoost-based machine learning for robust forecasting.Two optimization strategies,proximal policy optimization(PPO)and rule-based control(RBC),are developed for charge-discharge scheduling,explicitly incorporating grid stability metrics.Multi-scenario analysis evaluates performance under varying capacities and initial states of charge(SOC).Results demonstrate the hybrid model’s superiority over physics-based benchmarks,significantly improving prediction accuracy,with R2 increasing from 0.70 to 0.95 for SOC and from 0.83 to 0.98 for grid power.Both PPO and RBC enhance efficiency and stability versus baseline:the energy self-sufficiency rate rises from 10.6%to 79.3%(PPO)and 82.4%(RBC),while grid power fluctuations decrease from 2.6 kWh to 1.66 kWh(PPO)and 1.38 kWh(RBC).Crucially,RBC achieves higher stability and interpretability near boundaries,whereas PPO excels in long-term optimization but exhibits boundary-condition sensitivity.Results further reveal that PV-battery capacity and initial SOC influence strategy performance.This study establishes a structured technical pathway encompassing hybrid forecasting model development,stability-oriented optimization design,and scenario-based performance evaluation,providing an integrated solution to enhance grid resilience and energy autonomy in residential PV-battery systems.
文摘Two examples of the use of vortex control to reduce noise and enhance the stable operating range of a centrifugal compressor are presented in this paper.In the case of high-flow operation of a centrifugal compressor with a vaned diffuser,a discrete frequency noise induced by interaction between the impeller-discharge flow and the diffuser vane,which appears most notably in the power spectra of the radiated noise,can be reduced using a tapered diffuser vane(TDV) without affecting the performance of the compressor.Twin longitudinal vortices produced by leakage flow passing through the tapered portion of the diffuser vane induce secondary flow in the direction of the blade surface and prevent flow separation from the leading edge of the diffuser.The use of a TDV can effectively reduce both the discrete frequency noise generated by the interaction between the impeller-discharge flow and the diffuser surface and the broadband turbulent noise component.In the case of low-flow operation,a leading-edge vortex(LEV) that forms on the shroud side of the suction surface near the leading edge of the diffuser increases significantly in size and blocks flow in the diffuser passage.The formation of an LEV may adversely affect the performance of the compressor and may cause the diffuser to stall.Using a one-side tapered diffuser vane to suppress the evolution of an LEV,the stable operating range of the compressor can be increased by more than 12 percent,and the pressure-rise characteristics of the compressor can be improved.The results of a supplementary examination of the structure and unsteady behavior of LEVs,conducted by means of detailed numerical simulations,are also presented.
基金Supported by 973 National Basic Research Program of China(2013CBA01504)Natural Science Foundation of China NSFC(11121504,11334013,11175119,11374209)
文摘At Shanghai Jiao Tong University（SJTU） we have established a research laboratory for advanced acceleration research based on high-power lasers and plasma technologies. In a primary experiment based on the laser wakefield acceleration（LWFA） scheme, multi-hundred Me V electron beams of reasonable quality are generated using 20–40 TW, 30 femtosecond laser pulses interacting independently with helium, neon, nitrogen and argon gas jet targets. The laser-plasma interaction conditions are optimized for stabilizing the electron beam generation from each type of gas. The electron beam pointing angle stability and divergence angle as well as the energy spectra from each gas jet are measured and compared.
