作者机构：
[文韬; 代兴勇; 李浪; 刘豪] College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Hunan, Changsha, 410004, China
摘要：
Biomass based porous carbon is a green and low-cost promising adsorbents for CO2 capture. However, most of these porous carbon were prepared under high-temperature and even multistep pyrolysis, and possessed poor textural properties and controllability. Here, enzymatic hydrolysis lignin (EHL) was used as carbon source to prepare O-rich N-doped porous carbon (LNPC) through a synthesis strategy that coupled hydrothermal treatment, mechanochemical assistance, and low-temperature activation for the first time. These porous carbon had the large specific surface areas (602.2 similar to 2030.7 m(2)/g), high microporosity, and abundant ultramicroporous (V-ultra) (0.19 cm(3)/g), as well as significant N doping and high O content (30.93 similar to 55.32 %). And the effects of the coupling method, activation temperature, and mechanical pressure and residence time on structural properties of lignin based porous carbon were investigated in detail. We found that the residence time had a good linear correlation for surface areas and micropore volume, respectively, meanwhile, the mechanical pressing exhibited better linear correlation for O content of LNPC, implied the preparation method had good controllability. LSY-P20-T20 prepared at activation temperature of 600 degree celsius with the mechanical pressure and time (20 MPa and 20 min) had the highest V-ultra, and high O content, and possessed the highest CO2 uptake (5.00 mmol/g). Subsequently, we found that the narrow micropore volume (with d < 1.0 nm) was the main factor for CO2 adsorption capacity, while O content showed more significant impact on determining CO2/N-2 selectivity and isosteric heat of adsorption (Q(st)) of LNPCs. This work provided a new feasible approach for cost-effective carbon-based adsorbents for CO2 capture.
关键词：
Lithium-ion battery;Thermal regulation strategy;Spectral method;Thermoelectric cooler;Nonlinear model predictive control
摘要：
An efficient thermal regulation strategy is of great significance in ensuring the safe operation of electric vehicles (EVs). However, the commonly used thermal management systems suffer from the problem of not being able to accurately and uniformly control the temperature distribution of lithium-ion batteries (LIBs), which poses great risks to the thermal safety control of batteries. In this paper, an advanced thermal management system for LIBs based on thermoelectric cooler (TEC) was designed to overcome the above problems. First, a temperature regulation mechanism model for LIB was constructed. Then, a novel temperature distribution modeling method for TEC was developed by using spectral method. This modeling process took into account the unsteady heat transfer characteristics, which can achieve high modeling accuracy. Next, a state space model of temperature control was constructed by combining a differential model of LIB with the proposed cooler model. On this basis, a temperature control strategy for LIB using nonlinear model predictive control (NMPC) method was proposed to optimize the cooling process because of its superior processing ability to constraints and nonlinearity. A various of experiments and verifications demonstrated that the presented thermal regulation strategy was effective and feasible.
摘要：
The white-light-emitting devices (WLEDs) for urban ecological lighting remain the challenge. The current urban lighting system destroys the growth habits of plants and leads to inhibition of plant growth, reduced branching, smaller leaf area and reduced total dry weight due to excessive blue light. In this work, a series of blue -green and red dual-emission Na 3 Ba 2 Ca(PO 4 ) 3 :Eu 2+ , Mn 2+ phosphors have been successfully synthesized by the hightemperature solid -state reaction method. The crystal structure, the occupancy of the dopant ions and the luminescence characteristics were carefully investigated. The excitation and emission spectra as well as the decay lifetime confirm the effective energy transfer from Eu 2+ to Mn 2+ , which leads to a tunable luminescence with greatly reduced blue emission. Especially, the optimal Na 3 Ba 2 Ca(PO 4 ) 3 :0.02Eu 2+ , 0.11Mn 2+ phosphor demonstrates a high internal quantum yield of 99.7%. At 150 degrees C, the luminescence intensity of Na 3 Ba 2 Ca (PO 4 ) 3 :0.02Eu 2+ , 0.11Mn 2+ can maintain 64.5% of room temperature intensity. In addition, the WLED device fabricated with Na 3 Ba 2 Ca(PO 4 ) 3 :Eu 2+ , Mn 2+ phosphor shows white light emission with CIE coordinates of (0.3800, 0.3852), rendering index (Ra) of 65.4 and correlated color temperature (CCT) of 3640 K. These results confirm that the Na 3 Ba 2 Ca(PO 4 ) 3 :Eu 2+ , Mn 2+ phosphor can be applied as a white light source in the urban ecological field.
关键词：
Battery electric vehicle;Energy flow;Vehicle test;Integrated simulation;Driving cycles
摘要：
To comprehensively investigate the energy distribution and performance of a battery electric vehicle (BEV), an integrated simulation model based on energy flow test data was developed and validated, and the energy flow characteristics of the BEV throughout the entire driving range in low-temperature conditions were studied. The results show that the battery heat loss and motor energy loss first increase and then decrease with an increment in cycle number, while the transmission loss first decreases and then remains constant. The energy recovery efficiency demonstrates an incremental trend with the number of cycles post-battery charging, while the energy utilization efficiency experiences a decline due to escalating energy losses within the power distribution unit (PDU). The energy flow characteristics of the BEV exhibit a pronounced connection with the speed properties inherent in the driving cycle. The battery charge energy is maximal under Urban Dynamometer Driving Schedule (UDDS), whereas the electricity consumption per 100 km is minimized under China light-duty vehicle test cyclepassenger (CLTC-P). Conversely, the energy utilization and recovery efficiency are the highest under Worldwide Light-duty Test Cycle (WLTC). These findings provide directional insights, theoretical support and data basis for rational performance evaluation and optimal energy distribution of BEVs.
关键词：
District energy system (DES);Renewable energy;Game theory;Deep decarbonization;Subsidy strategy;Optimization
摘要：
Renewable district energy systems present a promising solution for decarbonizing the energy sector. However, optimal strategies to mitigate the financial challenges of deep decarbonization are still underexplored. This study aims to optimize government subsidy strategies and users' system designs to facilitate cost-effective deep decarbonization using game theory. Two indicators, the renewable generation rate (RGR) and the self-sufficiency rate (SSR), are formulated to understand the principles of achieving deep decarbonization. Additionally, the study introduces a new strategy called subsidy plus energy storage service (SUB + ESS), contrasting it with the traditional subsidy-only strategy. Key findings indicate that merely increasing the RGR requirements does not achieve deep decarbonization due to energy mismatches. Restricting the SSR requirements proves effective in achieving deep decarbonization but imposes a significant economic burden on the government. When the SSR requirement is set at 100%, carbon emissions are reduced by 93%, but the government's subsidy expenditure increases nearly fivefold. In contrast to the subsidy-only strategy, the novel SUB + ESS strategy, with a 100% SSR requirement, reduces government expenditure by approximately 52% and lowers total expenditure by 19.7%. A two-stage decarbonization strategy is proposed: initially, offering subsidies is sufficient, but as deeper decarbonization is pursued, establishing energy storage service becomes essential.
摘要：
The modulation mechanism of iron (Fe) and manganese (Mn) in transition-metal elements on the interface bonding and mechanical properties of bronze (Cu3Sn)-based/diamond composites is investigated through first-principles calculations. Transition-elements-doping scenarios are investigated employing six-layer slab models. It is revealed that the doping of Fe or Mn can make the Cu3Sn/diamond interface more stable, which effectively improves the wettability of the Cu3Sn/diamond interface based on the calculation results and analysis of interface energy, differential charge density model, and density of states. However, co-doping with both Fe and Mn weakens the wettability of the Cu3Sn/diamond interface. Finally, wettability tests and microstructure characterizations demonstrate that the doping of Fe and Mn represents an effective approach to controlling the interface bonding performance of bronze/diamond composites. Fe- and Mn-doping effects on the interface binding and mechanical properties of Cu3Sn/diamond composites are studied using first-principles calculations. Analysis of interface energy, charge density models, and density of states reveals that individual Fe or Mn doping improves Cu3Sn//diamond interface wettability. Conversely, co-doping weakens Cu3Sn/diamond interface wettability. Wettability tests and microscopic characterization validate these findings.image (c) 2023 WILEY-VCH GmbH
通讯机构：
[Yang, Y ] N;Northwestern Polytech Univ, Natl Key Lab Aerosp Flight Dynam, Youyi Rd, Xian 710072, Peoples R China.;Northwestern Polytech Univ, Res Ctr Intelligent Robot, Sch Astronaut, Youyi Rd, Xian 710072, Peoples R China.
关键词：
bilateral synchronization control;communication problem;networked teleoperation robot system;uncertainty problem
摘要：
<jats:title>Abstract</jats:title><jats:p>Bilateral synchronization control for Network Teleoperation Robot System (NTRS) in discrete domain is discussed in this paper, where time delay, data loss and disorder, and quantization error coexist. Firstly, it is assumed that time delay and data loss are asymmetric and randomly vary in the master–slave channel and slave–master channel according to different Markov jump change rules. By introducing the virtual variables, a clever normalization method is proposed for time delay or data loss. It not only uniforms time delay and data loss into a same framework, but also effectively handles the problem of data disorder. And then, a logarithmic quantizer is designed to dispose quantization error. Meanwhile, utilize the sector bound method to describe the quantization error and transform the quantization feedback control problem into a robust control problem, so the familiar robust control methods can be adopted to solve quantization problem. In addition, human and environmental forces are treated as external disturbances and processed using neural network techniques. Subsequently, stochastic stability and synchronization control property are guaranteed by the designed analogous PD controller that consists of proportion, derivative, and uncertainty estimation items. Finally, validity of the proposed method is certified by some simulation examples.</jats:p>
摘要：
Thus far, the available works on sequencing flexibility in shop floor scheduling only consider the sequencing flexibility with serial operation constraint. However, the sequencing flexibility with discrete and hybrid operation constraints are also widely existed in the actual production and have significant impact on production efficiency. Therefore, this work proposes a distributed flexible job shop scheduling problem considering integrated sequencing flexibility (DFJSPS), in which the serial, discrete and hybrid operation constraints are considered simultaneously. A mixed integer linear programming model is proposed to solve the DFJSPS by using the CPLEX solver. Then, an efficient memetic algorithm (EMA) is designed with the objectives of minimizing makespan and total energy consumption. In the EMA, a five-layer coding method and an efficient initialization method are presented to obtain high quality initial solutions; and an efficient local search operator is designed to help the algorithm to improve its convergence speed. Comprehensive experiments show that the EMA outperforms other three well-known algorithms in most of the instances, demonstrating the superior performance of EMA for solving DFJSPS in terms of both computational efficiency and solution quality. In summary, the research fills the research gap on integrated sequencing flexibility in the field of shop floor scheduling; on the other hand, it can help production managers to obtain the efficient scheduling schemas in the decision-making systems about various types of sequencing flexibility.
摘要：
This study proposes a new strategy for achieving rapid volumetric heating of moldable lowdielectric -loss glass over a wide temperature range using only microwave sources. As a proof of concept, both multi -physics modeling and experimental demonstration of microwave heating (MWH) of Pyrex 7740 glass are performed. The results reveal that there is an activation threshold of 400 degrees C for this glass, i.e., below this threshold the glass is mainly heated by SiC molds through interfacial heat transfer, while above it the glass can be directly heated by 2.45-GHz MWs volumetric dielectric loss. As a the can attain an internal ture of 727 degrees C (well above its transition point) within a short MWH process (130 s), at a low level of specific energy consumption (6.43 kW h/kg). The average volumetric heating rate of the glass is estimated as 5.44 degrees C/s, which outperforms the reported rates (2.00 - 3.60 degrees C/s) in previous precision glass molding (PGM) studies. Furthermore, the temperature difference in the entire glass can be minimized through MWH combined with post -annealing. With the demonstrated capabilities of instantaneous, volumetric, and selective heating, the proposed MWH strategy holds great promise in PGM and many other glass thermoforming sectors.
