A parallel paired electrosynthetic method, coupling electrocarboxylation incorporating CO
into ketone, imine, and alkene with alcohol oxidation or oxidative cyanation of amine, was developed for the ...first time. Various carboxylic acids as well as aldehyde/ketone or α-nitrile amine were prepared at the cathode and anode respectively in a divided cell. Its utility and merits on simultaneously achieving high atom-economic CO
utilization, elevated faradaic efficiency (FE, total FE of up to 166 %), and broad substrate scope were demonstrated. The preparation of pharmaceutical intermediates for Naproxen and Ibuprofen via this approach proved its potential application in green organic electrosynthesis.
Improving SO2/H2O resistance at low temperatures is a key challenge for industrial applications of NH3-SCR catalysts. Herein, a novel catalyst with remarkable low-temperature NH3-SCR activity and ...strong SO2/H2O resistance was designed by loading MoOx protective layer over porous kit-CeO2. The in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) coupled with basic characterization techniques were utilized to further elucidate the underlying mechanisms, and a dynamic balance between the deposition and decomposition of ammonia bisulfate was captured over porous kit-CeO2. Highly dispersed MoOx species pre-adsorbed with NH3 significantly curtailed the adsorption of NOx molecules, and the catalytic reaction over MoOx/kit-CeO2 primarily followed by the Eley-Rideal mechanism. At 250 °C, in the presence of SO2 and H2O, the Ce-O-Mo pairing site was almost unaffected and the super SO2- and H2O-tolerant property originated from the facilitated decomposition of ammonium bisulfate (ABS) and the shielding effect of Mo protective layer on SO2/H2O. This study provided an important guidance to the application of ceria-based catalysts for environmental control within low-temperature operations in non-power industries such as glass, steel, cement manufacturing, etc.
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•A catalyst with good NH3-SCR activity was designed by loading MoOx over kit-CeO2.•MoOx/kit-CeO2 shows strong SO2/H2O resistance.•The NH3-SCR reaction primarily followed by the Eley-Rideal mechanism.•MoOx/kit-CeO2 can facilitate decomposition of ammonium bisulfate.•MoOx protective layer on SO2/H2O shows the shielding effect.
Inertia drift is an aggressive transitional driving maneuver, which is challenging due to the high nonlinearity of the system and the stringent requirement on control and planning performance. This ...paper presents a solution for the consecutive inertia drift of an autonomous RC car based on primitive-based planning and data-driven control. The planner generates complex paths via the concatenation of path segments called primitives, and the controller eases the burden on feedback by interpolating between multiple real trajectories with different initial conditions into one near-feasible reference trajectory. The proposed strategy is capable of drifting through various paths containing consecutive turns, which is validated in both simulation and reality.
A mild and efficient type of Pd/Cu‐catalyzed allenamide allyl acetate reaction with terminal alkynes affording polyfunctionalized 2,3‐dihydropyrrole derivatives is reported. Allenamide substrates ...went through two π‐allyl palladium complex processes, and then it was trapped by terminal alkynes on the distal position via a Sonogashira reaction. Two new Csp3−Csp2 and Csp3−Csp bonds were efficiently constructed in one pot.
Working together: A mild and efficient type of Pd/Cu‐catalyzed allenamide allyl acetate reaction with terminal alkynes affording polyfunctionalized 2,3‐dihydropyrrole derivatives is reported. Two new Csp3−Csp2 and Csp3−Csp bonds were efficiently constructed in one pot.
In cases where the space available for the mechanically stabilized earth (MSE) walls is less than required, the “narrowed mechanically stabilized earth walls” are usually designed and constructed ...next to the existing stable slopes/walls. Although such walls have already been used and studied in some projects, the effects of different interface connections on complicated narrowed MSE walls are still not clear. The performance and mechanism of narrowed MSE walls still need further exploration, especially those with complex boundaries. Accordingly, two centrifuge model tests of narrowed MSE walls with thick soil mass above (like having an inside bench) were designed and carried out with full instrumentations. One of the models had mechanical interface connections to the boundary/stable slope and the other one without connections. The authors analyzed the experimental data including settlement, lateral displacement of the facing and earth pressure in the narrowed MSE walls and used limit equilibrium method to help locate critical failure planes. The results indicated that narrowed MSE walls had obvious differential settlement on crest, and around the inside bench the vertical earth pressure was observed to have concentrated and reduced distributions. The analyses indicated that the critical failure plane was bilinear, also different from conventional MSE walls. Mechanically connecting the narrowed MSE wall to the stable slope/wall is an efficient measure to help control the deformation and improve stability of the system, whereas the unconnected wall would experience larger displacement and was prone to collapse. Furthermore, the rupture of model reinforcements suggested that the extension of the upper reinforcements beyond the stable wall/slope face was not enough to ensure external stability.
When human walks down a slope, the center of gravity of the body leans backward to keep balance, meanwhile the friction between the heel and ground is increased. Considering this situation, a model ...of passive kneed biped with fixed feet is modeled in this paper. This type of passive models compensates the lost energy of collision by the potential energy when the knee is locked and the foot impacts the ground. Since different foot shapes lead to different energy lost in the heel collisions, the walking speed and energy consumption effected by various of foot shapes is discussed, and the suitable slopes for stable gait corresponding to different foot parameters is given. And these results are positive to design and debug our passive walking prototype.
Inertia drift is an aggressive transitional driving maneuver, which is challenging due to the high nonlinearity of the system and the stringent requirement on control and planning performance. This ...paper presents a solution for the consecutive inertia drift of an autonomous RC car based on primitive-based planning and data-driven control. The planner generates complex paths via the concatenation of path segments called primitives, and the controller eases the burden on feedback by interpolating between multiple real trajectories with different initial conditions into one near-feasible reference trajectory. The proposed strategy is capable of drifting through various paths containing consecutive turns, which is validated in both simulation and reality.
In this paper, we focus on the study of the simple Compass-like biped robot with controlled flat feet which can improve the stability of the dynamic walking under complex road conditions. A hybrid ...dynamic mathematical model of this biped robot based on the passive dynamic walking is modeled. Particularly, the hip-locked strike is proposed from the bionic perspective. The dynamics and energy efficiency of this kind of biped locomotion are analyzed. Then the energy consumption affected by foot length and slope angle during stable walking is analyzed to obtain the optimum ratio of foot length to leg length. It is proved by simulations that, in certain extent, the walking efficiency is proportional to the length of foot.
The gait stability of Passive Dynamic Walking is sensitive to the initial walking state, which must be adjusted precisely for continuous gaits. A novel torque shaping control method is proposed to ...obtain the initial stable gait for the passive dynamic walker within a gait period in this paper. Meantime, the stability of the system with this controller is proved. Therefore, the unstable initial state can be adjusted to generate stable limit cycles in the following steps. The performance of this controller is verified by simulations. It is more effective to against the disturbance and has faster convergence speed than traditional PD control.
This paper introduces the characteristics of the PADW-II robot's construction. PADW-II robot has an upper body which uses bisector mechanism. This structure is proved more efficient than other types ...of upper body. The robot can be concluded to finite state machine modal. The control system hardware is designed with ARM7-based embedded exploitation board which embedded μC/OS - II real time operating system. The control system has a hierarchical structure to improve the reliability and immunity for the system. The algorithm is also designed based on the FSM modal. To implement the algorithm, we develop the software based on μC/OS - II real time operation system, by which several different tasks are created to fulfill the states control of the robot. Some experiments have been done and the energy efficiency contrasting to some robots is given. In accordance with the characteristic of the control the conception of Under-actuated system is advanced at last.
