The hydrogen energy storage system(HESS)integrated with renewable energy power generation exhibits low reliability and flexibility under source-load *** address the above issues,a two-stage optimal scheduling model co...
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The hydrogen energy storage system(HESS)integrated with renewable energy power generation exhibits low reliability and flexibility under source-load *** address the above issues,a two-stage optimal scheduling model considering the operation sequences of HESSs is proposed for commercial community integrated energy systems(CIESs)with power to hydrogen and heat(P2HH)*** aims to optimize the energy flow of HESS and improve the flexibility of hydrogen production and the reliability of energy supply for ***,the refined operation model of HESS is established,and its operation model is linearized according to the operation domain of HESS,which simplifies the difficulty in solving the optimization problem under the premise of maintaining high approximate ***,considering the flexible start-stop of alkaline electrolyzer(AEL)and the avoidance of multiple energy conversions,the operation sequences of HESS are ***,a two-stage optimal scheduling model combining day-ahead economic optimization and intra-day rolling optimization is established,and the model is simulated and verified using the source-load prediction data of typical days in each *** simulation results show that the two-stage optimal scheduling reduces the total load offset by about 14%while maintaining similar operating cost to the day-ahead economic optimal ***,by formulating the operation sequences of HESS,the operating cost of CIES is reduced by up to about 4.4%.
The large number and dense layout of rail fastening can significantly affect the aerodynamic performance of *** the Improved Delayed Detached Eddy Simulation(IDDES)approach based on the SST(Shear Stress Transport)k-ω...
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The large number and dense layout of rail fastening can significantly affect the aerodynamic performance of *** the Improved Delayed Detached Eddy Simulation(IDDES)approach based on the SST(Shear Stress Transport)k-ωturbulent model,this study evaluates the effects of the rail fastening system on the aerodynamic force,slipstream and train wake under crosswind *** results indicate that in such conditions,compared to the model without rails,the rail and the fastening system reduce the drag force coefficient of the train by 1.69%,while the lateral force coefficients increase by 1.16%and 0.87%,*** aerodynamic force can be considered virtually unchanged within the error ***,the rail and the fastening system cause an inward shift of the negative pressure center on the leeward side of the *** peak slipstream velocity near the ground in the rail and rail fastening system model is significantly lower than that in the situation without ***,the rail and the fastening system not only induce two displacements in the vortex structure of the train but also accelerate the dissipation of shedding vortex and the rapid decrease of turbulent kinetic energy.
On the basis of novel properties of ferroelectric conducting domain walls,the domain wall nanoelectronics emerges and provides a brand-new dimension for the development of high-density,high-speed and energy-efficient ...
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On the basis of novel properties of ferroelectric conducting domain walls,the domain wall nanoelectronics emerges and provides a brand-new dimension for the development of high-density,high-speed and energy-efficient *** in-memory computing,three-terminal devices with both logic and memory functions such as transistors purely based on ferroelectric domain walls are urgently ***,a prototype ferroelectric domain-wall transistor with a well-designed coplanar electrode geometry is demonstrated on epitaxial Bi Fe O_(3)thin *** the logic function,the current switching between on/off states of the transistor depends on the creation or elimination of conducting domain walls between drain and source *** the data storage,the transistor can maintain nonvolatile on/off states after the write/erase operations,providing an innovative approach for the development of the domain wall nanoelectronics.
Effectively controlling active power-assist lower-limb exoskeletons in a human-in-the-loop manner poses a substantial chal-lenge,demanding an approach that ensures wearer autonomy while seamlessly adapting to diverse ...
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Effectively controlling active power-assist lower-limb exoskeletons in a human-in-the-loop manner poses a substantial chal-lenge,demanding an approach that ensures wearer autonomy while seamlessly adapting to diverse wearer *** paper introduces a novel hierarchical control scheme comprising five integral components:intention recognition layer,dynamics feedforward layer,force distribution layer,feedback compensation layer,as well as sensors and *** intention rec-ognition layer predicts the wearer's movement and enables wearer-dominant movement through integrated force and position *** force distribution layer effectively resolves the statically indeterminate problem in the context of double-foot support,showcasing flexible control *** dynamics feedforward layer mitigates the effect of the exoskeleton itself on ***,the feedback compensation layer provides reliable closed-loop *** approach mitigates abrupt changes in joint torques during frequent transitions between swing and stance phases by decomposed *** this innovative hierarchical control scheme on a hydraulic exoskeleton platform through a series of experiments,the results demonstrate its capability to deliver assistance in various modes such as stepping,squatting,and jumping while adapting seamlessly to different terrains.
Hybrid joint-space control strategy, where some redundant cables are force control, while other cables perform the length control, has the ability to control the robots with small pose errors, and maintain all ca...
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This paper presents a precision centimeter-range positioner based on a Lorentz force actuator using flexure *** additional digital-to-analog converter and an operational amplifier(op amp)circuit together with a suitab...
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This paper presents a precision centimeter-range positioner based on a Lorentz force actuator using flexure *** additional digital-to-analog converter and an operational amplifier(op amp)circuit together with a suitable controller are used to enhance the positioning accuracy to the nanometer ***,a suitable coil is designed for the actuator based on the stiffness of the flexure guide *** flexure mechanism and actuator performance are then verified with finite element *** on these,a means to enhance the positioning performance electronically is presented together with the control ***,a prototype is fabricated,and the performance is *** positioner features a range of 10 mm with a resolution of 10 *** proposed scheme can be extended to other systems.
This paper presents a general method for dynamic modeling of three-dimensional flexible manipulator with multiple degrees of freedom based on Lagrange’s second kind of dynamic equation. Firstly, the dynamic model of ...
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The oxidation behavior of a novel Ni-based single-crystal 4774DD1 superalloy for industrial gas turbine applications was investigated by the isothermal oxidation at 980℃ and discontinuous oxidation weight gain *** ph...
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The oxidation behavior of a novel Ni-based single-crystal 4774DD1 superalloy for industrial gas turbine applications was investigated by the isothermal oxidation at 980℃ and discontinuous oxidation weight gain *** phase constitution and morphology of surface oxides and the characteristics of the crosssection oxide film were analyzed by XRD,SEM and *** show that the oxidation kinetics of the 4774DD1 superalloy follows the cubic law,indicating its weak oxidation resistance at this *** the oxidation time increases,the composition of the oxide film evolves as following:One layer consisting of a bottom Al_(2)O_(3)sublayer and an upper(Al_(2)O_(3)+NiO)mixture sublayer after oxidized for 25 ***,two layers composed of an outermost small NiO discontinuous grain layer and an internal layer for 75 *** internal layer is consisted of the bottom Al_(2)O_(3)sublayer,an intermediate narrow CrTaO_(4)sublayer,and an upper(Al_(2)O_(3)+NiO)mixture *** two layers comprising an outermost relative continuous NiO layer with large grain size and an internal layer as the oxidation time increases to 125 *** internal layer is composed of the upper(Al_(2)O_(3)+NiO)mixture sublayer,an intermediate continuous(CrTaO_(4)+NiWO_(4))mixture sublayer,and a bottom Al_(2)O_(3)***,three layers consisting of an outermost(NiAl2O_(4)+NiCr2O_(4))mixture layer,an intermediate(CrTaO_(4)+NiWO_(4))mixture layer,and a bottom Al_(2)O_(3)layer for 200 h.
Landing mechanism tends to rebound and turn over,and the stability time is long when landing on the small celestial *** landing performance in different conditions is necessary to be evaluated to guide the ***,landing...
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Landing mechanism tends to rebound and turn over,and the stability time is long when landing on the small celestial *** landing performance in different conditions is necessary to be evaluated to guide the ***,landing performance evaluation is realized by *** factors affecting the landing performance including cardan element damping,foot anchors,retro-rocket thrust,landing slope angle,and landing attitude are analyzed.A microgravity platform is built to test the landing mechanism,and the consistency between the simulation and the experiment is *** the basis of simulation and experiment,some landing suggestions are proposed to improve the landing performance.
Owing to their remarkable flexibility and favorable cost-effectiveness,industrial robots have found extensive applications to cutting of materials across sophisticated manufacturing ***,the structurally low rigidity o...
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Owing to their remarkable flexibility and favorable cost-effectiveness,industrial robots have found extensive applications to cutting of materials across sophisticated manufacturing ***,the structurally low rigidity of these robots renders the tool tip prone to substantial oscillations during machining processes,significantly impacting product fabrication *** objective of this study is to present a novel methodology employing magnetorheological dampers for mitigating vibrations during robotic milling ***,a new type of ring nested Magneto-Rheological Foam Damper(MRFD)working in the squeeze mode is ***,the MRFD’s structure is designed considering the vibrational characteristics of robotic ***,a damping force model of the MRFD is *** feasibility of the MRFD’s structural design is validated by the finite element analyses,which is instrumental in comprehending the influence of structural parameters on the electromagnetic characteristics of the ***,a prototype of the MRFD is fabricated selecting appropriate ***,a series of excitation and milling experiments are conducted on a KUKA KR500 *** outcomes demonstrate a substantial reduction(37%-69%)in radial vibration amplitude at the tool tip during robotic milling,highlighting the effectiveness of the developed *** research endeavor has introduced a pioneering avenue and framework for vibration control in robotic milling,offering a novel paradigm for enhancing the precision of robotic machining.
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