Search

Antimicrobial peptides have received increased attention due to the increasing prevalence of antibiotic-resistant bacteria. However, the development of antimicrobial peptides for clinical applications remains a huge challenge. SPA ([D-rg

A high-quality and large-sized GdB6 single crystal was successfully prepared by using the optical floating zone method to accurately control the temperature and composition of the molten zone. A GdB6 [100] single crystal 25 mm in length and 5 mm in diameter was obtained. The full width at half-maximum (FWHM) of the X-ray rocking curves was 0.227°, which indicated that the as-grown GdB6 single crystal had a high quality. The maximum thermionic emission current density of the GdB6 single crystal was 6.73 A cm−2 at U = 4000 V and T = 1873 K, and the average work function was 2.99 eV. Combining first-principles calculations and experiments, the work function was found to monotonically increase as the size of the GdB6 single crystal changed from nanostructure (1D) to bulk (3D).

Directionally solidified (DS) LaB6 (001)-ZrB2 eutectic composite is successfully prepared by optical zone melting technique. The effect of the solidification rate on the microstructure and properties is systemically investigated. With the increase in the solidification rate from 20 to 100 mm/h, the eutectic rods present a homogeneous eutectic microstructure. The relationship between the average eutectic spacing and the solidification rate is established. The fracture toughness shows an obvious anisotropy. Crack deflection and crack bridging play important roles in improving the fracture toughness of the material. As the solidification rate is increased from 20 to 300 mm/h, the fracture toughness, bending strength and current density firstly increase and then decrease. The highest fracture toughness of 5.16 MPa.m1/2, bending strength of 809.04 MPa and current density of 36.24 A/cm2 at 1873 K belong to the DS LaB6 (001) - ZrB2 eutectic composite obtained at V = 100 mm/h.

Considering battery aging and reducing CPU calculation pressure of electric vehicle, real-time assurance of the accuracy of power battery SOC and capacity is very important for the safety of electric vehicles. In this paper, a combined framework of battery SOC and capacity estimation is introduced based on equivalent circuit model. For the problem of traditional Kalman filter that only Gaussian noise can be filtered. An improved extended Kalman filter is proposed to estimate the battery SOC in real time. The accelerated aging experiment method is used to study the effect of the gray model in predicting battery capacity decline and the cumulative error of SOC estimation under battery aging. Through static and dynamic test experiments, the accuracy and robustness of the method proposed in this paper are verified.

Accurate control of fuel cell air supply system is critical to fuel cell system output efficiency and life. However, due to air compressor, back pressure valve, pipeline and other auxiliary components of the air system, the system state variables have complex nonlinear coupling and response delay problems, which make the control extremely difficult. In addition, the critical state variables of the system, such as the air flow, cannot be measured, which further increases the difficulty of the air system control. In this paper, a decoupled control architecture based adaptive observer is proposed to improve the control accuracy of transient conditions. First of all, a control-oriented air system model is designed in this paper. And then, an adaptive observer for inlet air flow and cathode pressure is developed based on the model and its stability is proved by using the stability theory method. Finally, An observer-based closed-loop decoupling control algorithm is designed and an experiment is conducted in hardware-in-loop test equipment. The experimental result shows that the observer proposed in this paper can accurately estimate the key variables of the system and ensure the stability, and the control architecture proposed in this paper can realize the precise decoupling control of the air system.

Mobile Edge Computing (MEC) refers to the concept of placing computational capability and applications at the edge of the network, providing benefits such as reduced latency in handling client requests, reduced network congestion, and improved performance of applications. The performance and reliability of MEC are degraded significantly when one or several edge servers in the cluster are overloaded. Especially when a server crashes due to the overload, it causes service failures in MEC. In this work, an adaptive admission control policy to prevent edge node from getting overloaded is presented. This approach is based on a recently-proposed low complexity RL (Reinforcement Learning) algorithm called SALMUT (Structure-Aware Learning for Multiple Thresholds), which exploits the structure of the optimal admission control policy in multi-class queues for an average-cost setting. We extend the framework to work for node overload-protection problem in a discounted-cost setting. The proposed solution is validated using several scenarios mimicking real-world deployments in two different settings - computer simulations and a docker testbed. Our empirical evaluations show that the total discounted cost incurred by SALMUT is similar to state-of-the-art deep RL algorithms such as PPO (Proximal Policy Optimization) and A2C (Advantage Actor Critic) but requires an order of magnitude less time to train, outputs easily interpretable policy, and can be deployed in an online manner., Comment: 16 pages

Aiming at the four-wheel drive hybrid structure, this paper aims at minimizing fuel consumption, takes full account of vehicle status, and designs a control strategy of working mode management and rule-based multi-power source energy allocation. In order to further improve the rationality of energy distribution, the ratio K of the demand torque to the optimal torque and SOC are the two inputs of the fuzzy controller, and engine torque working coefficient y is an output of fuzzy controller. The fuzzy control system is designed and the fuzzy control rules are established to optimize the engine working torque in real time. The simulation results show that the energy management strategy of the fuzzy optimal control accords with the demand of power train, realizes the smooth switching of working mode, reduces the speed error obviously, and improves the fuel economy by 7.81%.

The air supply system control strategy is a significant challenge issue of PEM(Polymer Electrolyte Membrane) fuel cells. In this paper, an observer-based model predictive control scheme is proposed for oxygen excess ratio control to avoid the oxygen starvation without using physical sensor of oxygen excess ratio based on a nonlinear dynamic model. Firstly, a sliding mode PI observer is proposed to estimate the cathode pressure and oxygen excess ratio, and the convergence is also discussed by a constructed Lyapunov function. Then, the observer-based model predictive controller is designed for the oxygen excess ratio control. Finally, the simulation validation is demonstrated to validate the effectiveness of the proposed observer and the control scheme by a high fidelity model.

The parameter matching and Simulation of multi-power source hybrid components are carried out according to its specific working principles and configuration characteristics. Fully consider the dynamic and economic indicators of the whole vehicle, In order to reduce the power loss of motor, the matching principle of power demand and high efficiency working point is adopted to select the parameters of driving motor, generator and engine. Based on CRUISE, a controlled object model of the whole vehicle is built, and the parameters of the matching power components are simulated under the typical Chinese public transportation conditions. The simulation results show that the multi-power source hybrid components matched by the combination of power and efficient working points can better meet the requirements of the vehicle power economy

The high-quality LaxCeyPr1-x-yB6 (x = 0.6–0.8, y = 0.1–0.3) single crystals have been firstly grown by optical floating zone melting method. The crystal structure, mechanical and thermionic emission properties of the as-grown single crystals were characterized by X-ray single crystal diffractometer, SEM, XRD, X-ray Laue diffraction. Subgrain-boundary-free [100] LaxCeyPr1-x-yB6 single crystal with a good crystalline integrity and homogeneous element distribution is obtained. The Lattice constant of LaxCeyPr1-x-yB6 single crystal is lower than that of the LaB6 single crystal. The lowest FWHM of 162.0 arcsec belongs to the La0.6Ce0.3Pr0.1B6 single crystal. The highest thermionic emission current density of 105.10 A/cm2 and the lowest work function of 2.562 eV indicate that La0.6Ce0.3Pr0.1B6 single crystal is a very promising thermionic cathode material.

According to the working principles and configuration characteristics of the series-parallel hybrid powertrain, the parameters of the hybrid components are calculated and optimized. Using performance as requirements, power and efficiency are matched toget the fundamental parameters of the engine, motor and generator. Based on the CRUSIE software, the vehicle model is built. The matching series-parallel powertrain parameters are simulated and verified. The results show that the matched series-parallel hybrid powertrain parameters can be well suited to the performance requirements of 10.5m buses.

© 2019 SAE International. All Rights Reserved. Electric vehicles are considered as one of the most popular way to decrease the consumption of petroleum resources and reduce environmental pollutions. Motor control system is one of the most important part of electric vehicles. It includes power supply module, IGBT driver, digital signal processing (DSP) controller, protection adjustment module, and resolver to digital convertor. To implement the control strategies on motor control system, a lot of practical aspects need to be taken into accounts. It includes setup of the initial excitation current, consistency of current between motor and program code, over-modulation, field weakening control, current protection, and so on. In this paper, an induction motor control system for electric vehicles is developed based on DSP. The control strategy is based on the field-oriented control (FOC) and space vector pulse width modulation (SVPWM). Speed calculation, over-modulation, field weakening control, PI controller, and fault diagnosis are also applied in this DSP algorithm. As an industry product running on a real electric bus with a 100kW induction motor, communication with vehicle control unit (VCU) by CAN bus, control system safety and PC software designed for lab experiments are also discussed. This paper focused on how to develop the advanced motor control system for electric vehicles for industrial application. The steady-state and transient performances of this motor control system are analyzed by both test-bench experiments and road experiments. Its performance is satisfactory when applied to the real electric vehicle.

The fuel economy and battery charge sustaining capability are two key criteria for the energy management of a full-power fuel cell hybrid vehicle equipped with small-capacity battery pack. In order to achieve stable battery charge sustenance and near-optimal fuel consumption, this study proposes an optimization-oriented adaptive equivalent consumption minimization strategy (A-ECMS) based on demand power prediction achieved via an iterative predictor. The proposed strategy updates the optimal equivalent factor periodically via local optimization process according to the predicted power to converge the state of charge (SOC) and guarantee fuel economy. The simulation results show that the iterative predictor has considerable accuracy, and the correlation between the predicted data and the real data reaches up to 0.987. The proposed strategy can quickly recover the battery SOC within 40 s in a 500-s driving cycle, which is shorter than existing feedback-oriented A-ECMS. At charge sustaining stage, the proposed strategy maintains the battery SOC around the reference value with an extremely low fluctuation degree of 0.36. The equivalent fossil-fuel consumption of the proposed strategy is 8.003 L/100 km, which is lower than that of existing A-ECMS. Besides, further investigation reveals that the proposed strategy has robust performance against the disturbance of power prediction errors.

Reactivity controlled compression ignition (RCCI) is demonstrated as a promising combustion strategy to achieve high efficiency and clean combustion. However, less effort has been devoted to examine the achievable RCCI operational range over a wide range of engine speed. In addition, previous studies have found that superior EGR rate and high diesel/gasoline fuel ratio are required to ease the extension of the low-load operating range of RCCI regime. Even then, relatively high CO and HC (unburned hydrocarbon) emissions and the accompanying fuel con-sum ption penalty still remain a problem to be resolved. Therefore, in this work the potential of diesel-fueled LTC to achieve simultaneously low NOx and soot emissions while maintaining high thermal efficiency at low load (IMEP ≈0.23–0.26 MPa) is investigated and compared with the gasoline/diesel RCCI strategy. The results show that the diesel LTC operation can yield slightly higher soot and NOx emissions (soot: 0.002 g/kW h, NOx: 0.446 g/kW h), but CO and HC emissions as well as the fuel consumption are much lower than the RCCI strategy, implying the diesel LTC regime may be more suitable for low-load operations. In addition, the RCCI operational range at speeds ranging from 900 to 2500 r/min is determined, the results show that the maximum achievable load (IMEP) increases with an increase in speed, and a maximum IMEP of 1.2 MPa can be achieved at an engine speed of 2300 r/min. Ultra-low NOx and soot emissions (soot

This paper introduces the structure and working principle of distributed hybrid vehicles, the simulation model of vehicle has been built by graphical modeling of MATLAB/Simulink. The multi parameter logic threshold optimization work region of driving control strategy based on the engine optimal work region was proposed, which considers the rational work region of battery with the boundary velocity threshold. Based on Matlab/Simulink, 0-32km/h acceleration simulation was carried out. The simulation results show that the designed multi parameter logic threshold drive control strategy can reasonably allocate the target torque of the engine and the motor. While ensuring that the engine and battery pack operate in a better working area, the power performance of the vehicle is improved.