摘要：
Proactive maintenance is widely recognized for enhancing equipment reliability and reducing downtime costs. However, its role in optimizing spare parts production and distribution decisions remains underexplored, thereby limiting efficient cross-domain resource utilization within the supply-demand system. This paper addresses this gap by studying a maintenance-driven multi-stage joint optimization problem (MMJOP), which integrates flexible spare parts production, multi-vehicle distribution, and imperfect maintenance. We propose an optimal imperfect maintenance strategy to link these cross-domain business activities precisely, and further develop a mathematical model aimed at minimizing energy consumption on the supply side and operational costs on the demand side. To solve the MMJOP, we design an enhanced non-dominated neighbor immune algorithm, featuring a customized initialization operator and a problem-specific local search operator. Additionally, a Q -learning mechanism is employed to automatically select the most appropriate key parameters in the proposed algorithm. Extensive experiments indicate that: (1) the proposed components greatly enhance QNNIA's search performance; and (2) the QNNIA outperforms four well-known comparison algorithms regarding computational optimality, convergence, distribution, and stability. More importantly, the proposed model yields significant economic value, i.e., saving operational costs by 49% with negligible impact on overall energy consumption, proving the necessity of cross-domain business cooperation and resource optimization in the high-end equipment industry.
Proactive maintenance is widely recognized for enhancing equipment reliability and reducing downtime costs. However, its role in optimizing spare parts production and distribution decisions remains underexplored, thereby limiting efficient cross-domain resource utilization within the supply-demand system. This paper addresses this gap by studying a maintenance-driven multi-stage joint optimization problem (MMJOP), which integrates flexible spare parts production, multi-vehicle distribution, and imperfect maintenance. We propose an optimal imperfect maintenance strategy to link these cross-domain business activities precisely, and further develop a mathematical model aimed at minimizing energy consumption on the supply side and operational costs on the demand side. To solve the MMJOP, we design an enhanced non-dominated neighbor immune algorithm, featuring a customized initialization operator and a problem-specific local search operator. Additionally, a Q -learning mechanism is employed to automatically select the most appropriate key parameters in the proposed algorithm. Extensive experiments indicate that: (1) the proposed components greatly enhance QNNIA's search performance; and (2) the QNNIA outperforms four well-known comparison algorithms regarding computational optimality, convergence, distribution, and stability. More importantly, the proposed model yields significant economic value, i.e., saving operational costs by 49% with negligible impact on overall energy consumption, proving the necessity of cross-domain business cooperation and resource optimization in the high-end equipment industry.
摘要：
Based on the investigation of mechanical response and microstructure evolution of a commercial 7003 aluminum alloy under high-speed impact, a new simple and effective method was proposed to determine the critical strain required for the nucleation of adiabatic shear band (ASB). The deformation results of cylindrical and hat-shaped samples show that the critical strain required for ASB nucleation corresponds to the strain at the first local minimum after peak stress on the first derivative curve of true stress−true strain. The method of determining the critical strain for the nucleation of ASB through the first derivative of the flow stress curve is named the first derivative method. The proposed first derivative method is not only applicable to the 7003 aluminum alloy, but also to other metal materials, such as commercial purity titanium, WY-100 steel, and AM80 magnesium alloy. This proves that it has strong universality.
Based on the investigation of mechanical response and microstructure evolution of a commercial 7003 aluminum alloy under high-speed impact, a new simple and effective method was proposed to determine the critical strain required for the nucleation of adiabatic shear band (ASB). The deformation results of cylindrical and hat-shaped samples show that the critical strain required for ASB nucleation corresponds to the strain at the first local minimum after peak stress on the first derivative curve of true stress−true strain. The method of determining the critical strain for the nucleation of ASB through the first derivative of the flow stress curve is named the first derivative method. The proposed first derivative method is not only applicable to the 7003 aluminum alloy, but also to other metal materials, such as commercial purity titanium, WY-100 steel, and AM80 magnesium alloy. This proves that it has strong universality.
摘要：
In this article, the concept of topological rainbow is introduced into the plate-mode waves system of 1D phononic crystal slabs, achieving adjustable topological elastic rainbow trapping by employing gradient-tuned Su-Schrieffer-Heeger (SSH) structures. First, based on the classical SSH model, a phononic crystal slab composed of steel and aluminum is set up, and the band structure of plate-mode waves is studied using the finite-element method. Band inversion can be induced by changing the height of the steel in the unit cell, leading to topological phase transitions. Then, phononic crystals with different topological properties are connected to form a phononic crystal slab, realizing topological interface states. Furthermore, a sandwich-like ultrathin structure is constructed to couple the adjacent two topological interface states. Finally, a 1D alternating SSH structure of phononic crystal slab is designed under gradient structural parameters, and based on eigenfrequency and full-wave simulation, adjustable topological rainbow trapping based on coupled interface states is achieved. The designed device can trap wide frequencies exceeding 15 kHz, providing more possibilities for the design of elastic-energy-harvesting devices. Topological rainbow in 1D phononic crystal slabs, achieving adjustable elastic trapping using gradient-tuned Su-Schrieffer-Heeger structures, is introduced. By varying steel heights, band inversion induces topological phase transitions, forming interface states. A sandwich-like structure couples these interface states, enabling rainbow trapping frequencies exceeding 15 kHz, outside the common bandgap, expanding design possibilities for energy-harvesting devices.image (c) 2024 WILEY-VCH GmbH
期刊：
Separation and Purification Technology,2025年353:128472 ISSN：1383-5866
通讯作者：
Xiancheng Ma<&wdkj&>Liqing Li<&wdkj&>Jiayong Si
作者机构：
[Xue, Ruiqi; Xu, Wenjun; Ma, Xiancheng; Si, Jiayong] College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha 410004, Hunan, China;[Guo, Yang; Zeng, Zheng; Li, Liqing] School of Energy Science and Engineering, Central South University, Changsha 410083, Hunan, China
通讯机构：
[Xiancheng Ma; Jiayong Si] C;[Liqing Li] S;College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha 410004, Hunan, China<&wdkj&>School of Energy Science and Engineering, Central South University, Changsha 410083, Hunan, China
摘要：
The preparation of efficient CO2 adsorbents is crucial for CO2 capture. Compared to polymer-based carbons and metal-organic frameworks (MOFs), biomass-based carbon exhibits lower adsorption performance. Here, we prepared high oxygen doped ultramicroporous carbon through hydrothermal treatment and mechanical compaction assisted KOH activation. The study found that mechanical compaction treatment can target a 24 % increase in the volume of ultra-micropores, resulting in a CO2 capture of the prepared ultramicroporous carbon reaching 5.6 mmol g−1, which is 22 % higher than that of conventionally prepared porous carbon. Molecular simulation calculations roughly estimated that functional groups and pore structures contribute 60 % and 40 %, respectively, to CO2 capture at 0.15 bar, and 47 % and 53 % at 1 bar. Meanwhile, we found that the selectivity of CO2/N2 is mainly related to the trend of oxygen functional groups, and is not significantly correlated with the micropore volume smaller than 0.7 nm. Theoretical calculations revealed that the introduction of oxygen groups into porous carbon resulted in an increase in selectivity of over 150 %, which is stronger than the effect of pore structure. This work provides valuable theoretical and experimental support for the design, preparation, and application of adsorbents for capturing CO2 in flue gas.
The preparation of efficient CO2 adsorbents is crucial for CO2 capture. Compared to polymer-based carbons and metal-organic frameworks (MOFs), biomass-based carbon exhibits lower adsorption performance. Here, we prepared high oxygen doped ultramicroporous carbon through hydrothermal treatment and mechanical compaction assisted KOH activation. The study found that mechanical compaction treatment can target a 24 % increase in the volume of ultra-micropores, resulting in a CO2 capture of the prepared ultramicroporous carbon reaching 5.6 mmol g−1, which is 22 % higher than that of conventionally prepared porous carbon. Molecular simulation calculations roughly estimated that functional groups and pore structures contribute 60 % and 40 %, respectively, to CO2 capture at 0.15 bar, and 47 % and 53 % at 1 bar. Meanwhile, we found that the selectivity of CO2/N2 is mainly related to the trend of oxygen functional groups, and is not significantly correlated with the micropore volume smaller than 0.7 nm. Theoretical calculations revealed that the introduction of oxygen groups into porous carbon resulted in an increase in selectivity of over 150 %, which is stronger than the effect of pore structure. This work provides valuable theoretical and experimental support for the design, preparation, and application of adsorbents for capturing CO2 in flue gas.
摘要：
We propose a simple and effective strategy to improve the high-temperature sensing characteristics of fiber Bragg gratings (FBGs) by introducing compressive stress into the grating structure by means of torsion assisted. Specifically, comparative analysis reveals that the torsion-assisted FBG has exhibited better high-temperature stability within the temperature range of 200∼800 °C as evidenced by a decay rate of 0.0064 dB/°C, which is significantly lower than the bare FBG (0.0081 dB/°C). Careful investigation shows that the thermal decay of the FBG can be further mediated by regulating the applied torsion and the simulation analysis has demonstrated that applied torsion can effectively introduce compressive stresses into the grating. Moreover, the torsion-assisted FBG also shows better high-temperature wavelength stability, slower heating decay rate, and improved wavelength hysteresis. In addition, the high-temperature strain characteristics of the torsion-assisted FBGs have also been investigated. Given the merits such as easy implementation, no need for complex heat treatment processes, good controllability, and low cost, we envision that the torsion-assisted FBG is promising in the field of high-temperature sensing.
摘要：
Dry machining has become one of the most promising and sustainable manufacturing processes in mechanical machining. One of the main puzzles for industrial applications of dry machining is tool wear, which are closely related with the transient thermomechanical characteristics of tool-chip interface (TCI). Simultaneously, those characteristics at micro scale can provided the critical insight of cutting mechanics and tool wear in ultrasonic vibration assisted cutting (UVC). However, reports in literature appear to be scarce. In this study the transient model of thermomechanical behavior in TCI is proposed, with a consideration of characteristics changes induced by ultrasonic vibration, as well as a focus on the transient cutting mechanism, as well as stress and friction. The proposed model is validated by comparison with the experimental and published analytical results. Obtained results from the proposed model indicate that the distribution of normal stress and average shear stress are similar to those that are predicted by Zorev's model. However, a noticeable apparent discrepancy appears between the two models regarding the distribution of shear stress. Apparently, the ultrasonic vibration changes the friction via alternating normal and shear stresses, and delays the time for the cutting force and the stress to reach their peak point. Additionally, it is confirmed that the fluctuation and increment of friction coefficient is due to the cutting force reduction in UVC under sustainable dry conditions.
Dry machining has become one of the most promising and sustainable manufacturing processes in mechanical machining. One of the main puzzles for industrial applications of dry machining is tool wear, which are closely related with the transient thermomechanical characteristics of tool-chip interface (TCI). Simultaneously, those characteristics at micro scale can provided the critical insight of cutting mechanics and tool wear in ultrasonic vibration assisted cutting (UVC). However, reports in literature appear to be scarce. In this study the transient model of thermomechanical behavior in TCI is proposed, with a consideration of characteristics changes induced by ultrasonic vibration, as well as a focus on the transient cutting mechanism, as well as stress and friction. The proposed model is validated by comparison with the experimental and published analytical results. Obtained results from the proposed model indicate that the distribution of normal stress and average shear stress are similar to those that are predicted by Zorev's model. However, a noticeable apparent discrepancy appears between the two models regarding the distribution of shear stress. Apparently, the ultrasonic vibration changes the friction via alternating normal and shear stresses, and delays the time for the cutting force and the stress to reach their peak point. Additionally, it is confirmed that the fluctuation and increment of friction coefficient is due to the cutting force reduction in UVC under sustainable dry conditions.
摘要：
In order to achieve carbon neutrality in transportation sector, this study examines the performance of three different fuels in a spark ignition (SI) engine from green and renewable methanol and hydrogen: M0G100 (pure gasoline), M10G90 (90 % gasoline mixed with 10 % methanol), M30G70 (70 % gasoline mixed with 30 % methanol), and M30G70 with hydrogen (7.5 % hydrogen energy share in blended fuel). The study explores the synergistic optimization influences of adding methanol and hydrogen on performance of a gasoline SI engine thorough comparative analysis. The results show that using hydrogen and methanol can improve combustion process of the gasoline engine. The coefficient of variation (COV) of peak combustion pressure for the test gasoline engine using different fuel mixtures (M0G100, M10G90, M30G70, and M30G70/hydrogen) is 16.25 %, 17.58 %, 18.75 %, and 9.55 % respectively. Similarly, the COV of indicated mean effective pressure for these mixtures is 7.6 %, 11.41 %, 33.45 %, and 4.41 % respectively. Additionally, using M30G70 with hydrogen in gasoline engine shows a 14.3 % decrease in fuel consumption and a 12.5 % increase in indicated thermal efficiency. The carbon dioxide (CO2) emissions of the test gasoline engine with M10G90, M30G70 and M30G70/hydrogen fuels are respectively reduced by 7.37 %, 26.78 % and 33.27 % compared to the gasoline engine.
In order to achieve carbon neutrality in transportation sector, this study examines the performance of three different fuels in a spark ignition (SI) engine from green and renewable methanol and hydrogen: M0G100 (pure gasoline), M10G90 (90 % gasoline mixed with 10 % methanol), M30G70 (70 % gasoline mixed with 30 % methanol), and M30G70 with hydrogen (7.5 % hydrogen energy share in blended fuel). The study explores the synergistic optimization influences of adding methanol and hydrogen on performance of a gasoline SI engine thorough comparative analysis. The results show that using hydrogen and methanol can improve combustion process of the gasoline engine. The coefficient of variation (COV) of peak combustion pressure for the test gasoline engine using different fuel mixtures (M0G100, M10G90, M30G70, and M30G70/hydrogen) is 16.25 %, 17.58 %, 18.75 %, and 9.55 % respectively. Similarly, the COV of indicated mean effective pressure for these mixtures is 7.6 %, 11.41 %, 33.45 %, and 4.41 % respectively. Additionally, using M30G70 with hydrogen in gasoline engine shows a 14.3 % decrease in fuel consumption and a 12.5 % increase in indicated thermal efficiency. The carbon dioxide (CO2) emissions of the test gasoline engine with M10G90, M30G70 and M30G70/hydrogen fuels are respectively reduced by 7.37 %, 26.78 % and 33.27 % compared to the gasoline engine.
摘要：
Road cracks pose a serious threat to the stability of road structures and traffic safety. Therefore, this paper proposes an optimized accurate road crack segmentation network called MBGBNet, which can solve the problems of complex background, tiny cracks, and irregular edges in road segmentation. First, multi-scale domain feature aggregation is proposed to address the interference of complex background. Second, bidirectional embedding fusion adaptive attention is proposed to capture the features of tiny cracks, and finally, Gaussian weighted edge segmentation algorithm is proposed to ensure the accuracy of crack edge segmentation. In addition, this paper uses the preheated bat optimization algorithm, which can quickly determine the optimal learning rate to converge the equilibrium. In the validation experiments on the self-built dataset, mean intersection over union reaches 80.54% and precision of 86.38%. MBGBNet outperforms the other seven state-of-the-art crack segmentation networks on the three classical crack datasets, highlighting its advanced segmentation capabilities. Therefore, MBGBNet is an effective auxiliary method for solving road safety problems.
作者机构：
[Zhi-Wei Luo] School of Materials Science and Engineering, Central South University, Changsha, 410083, PR China;Science Center for Phase Diagram & Materials Design and Manufacture, Central South University, Changsha, 410083, PR China;School of Materials Science and Engineering & Guangxi Key Laboratory of Information Materials, Guilin University of Electronic Technology, Guilin, 541004, PR China;[Jia-Yong Si] College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha, 410004, PR China;[Gui-Hua Li] School of Materials Science and Engineering, Central South University, Changsha, 410083, PR China<&wdkj&>Science Center for Phase Diagram & Materials Design and Manufacture, Central South University, Changsha, 410083, PR China<&wdkj&>School of Materials Science and Engineering & Guangxi Key Laboratory of Information Materials, Guilin University of Electronic Technology, Guilin, 541004, PR China
通讯机构：
[Ge-Mei Cai] S;School of Materials Science and Engineering, Central South University, Changsha, 410083, PR China<&wdkj&>Science Center for Phase Diagram & Materials Design and Manufacture, Central South University, Changsha, 410083, PR China
摘要：
Near-infrared (NIR) light sources have important applications in biomedical detection, food inspection, biochemical sensing, night vision, and other fields. Developing a broadband NIR luminescent material with multifunction will help the application and promotion of NIR light sources in various fields. This work designed Cr 3+ to occupy the weaker crystal field sites in the phosphate KInP 2 O 7 (KIPO) lattice for achieving NIR phosphors with a broad emission band. Under 472 nm excitation, KIPO: Cr 3+ exhibits NIR broadband emission centering ∼900 nm owing to the 4 T 2 → 4 A 2 transition of Cr 3+ in InO 6 . The full width at half maximum (FWHM) is as large as 175 nm as its weak crystal field strength. Besides, the emission intensity, FWHM, and fluorescence lifetime of KIPO: 0.05Cr 3+ were systematically investigated in response to temperature. A wide range of highly temperature-sensitive performances (1.92 % K −1 @ 423 K and 1.67 % K −1 @ 393 K) from 298 K to 573 K were obtained. Meanwhile, KIPO: 0.05Cr 3+ phosphors were encapsulated with a 660 nm LED chip to obtain a red-NIR pc-LED, demonstrating the potential application of the newly developed valuable NIR phosphors for oxygen saturation detection. This work hatches out a new idea for the development of new multifunctional NIR luminescent materials integrating optical temperature sensing and blood oxygen detection.
Near-infrared (NIR) light sources have important applications in biomedical detection, food inspection, biochemical sensing, night vision, and other fields. Developing a broadband NIR luminescent material with multifunction will help the application and promotion of NIR light sources in various fields. This work designed Cr 3+ to occupy the weaker crystal field sites in the phosphate KInP 2 O 7 (KIPO) lattice for achieving NIR phosphors with a broad emission band. Under 472 nm excitation, KIPO: Cr 3+ exhibits NIR broadband emission centering ∼900 nm owing to the 4 T 2 → 4 A 2 transition of Cr 3+ in InO 6 . The full width at half maximum (FWHM) is as large as 175 nm as its weak crystal field strength. Besides, the emission intensity, FWHM, and fluorescence lifetime of KIPO: 0.05Cr 3+ were systematically investigated in response to temperature. A wide range of highly temperature-sensitive performances (1.92 % K −1 @ 423 K and 1.67 % K −1 @ 393 K) from 298 K to 573 K were obtained. Meanwhile, KIPO: 0.05Cr 3+ phosphors were encapsulated with a 660 nm LED chip to obtain a red-NIR pc-LED, demonstrating the potential application of the newly developed valuable NIR phosphors for oxygen saturation detection. This work hatches out a new idea for the development of new multifunctional NIR luminescent materials integrating optical temperature sensing and blood oxygen detection.
期刊：
Renewable and Sustainable Energy Reviews,2025年219:115847 ISSN：1364-0321
通讯作者：
Xiongbo Duan
作者机构：
[Chenghao Wu] College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha 410004, China;[Jianqin Fu; Jingping Liu] State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082, China;[Xiongbo Duan; Zhiqiang Sun] Hunan Engineering Research Center of Clean and Low-Carbon Energy Technology, School of Energy Science and Engineering, Central South University, Changsha 410083, China;[Feng Zhou] College of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha 410004, China<&wdkj&>State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082, China
通讯机构：
[Xiongbo Duan] H;Hunan Engineering Research Center of Clean and Low-Carbon Energy Technology, School of Energy Science and Engineering, Central South University, Changsha 410083, China
摘要：
Fossil fuel use raises concerns regarding environmental pollution and limited storage capacity. Internal combustion engines significantly depend on the conventional gasoline and diesel, emphasizing the need for alternative fuels. Hydrogen is currently gaining attention as a potential clean energy alternative to traditional fossil fuels owing to its zero carbon emissions, high energy density, fast refueling, compatibility with the existing infrastructure, flexibility, and versatility. Hydrogen use in internal combustion engines signifies a paradigm shift in the engine community toward cleaner and more sustainable transportation solutions. However, challenges such as production costs, distribution infrastructure, and security requirements must be addressed for widespread use. Ongoing research aims to overcome these challenges and enhance the feasibility of using hydrogen as a carbon-free energy source for the engines. This study comprehensively overviews recent research progress and advancements in hydrogen internal combustion engine in terms of the mixture formation mechanism, combustion modes, abnormal combustion mechanism, and the formation mechanism of the nitrogen oxide emissions. In addition, advanced combustion control strategies and technologies have been proposed and summarized to regulate abnormal combustion and nitrogen oxide emissions in the hydrogen engine. The main objectives of this study are to overcome or address these challenges and problems and further enhance the feasibility of hydrogen as a carbon-free alternative fuel for the engine.
Fossil fuel use raises concerns regarding environmental pollution and limited storage capacity. Internal combustion engines significantly depend on the conventional gasoline and diesel, emphasizing the need for alternative fuels. Hydrogen is currently gaining attention as a potential clean energy alternative to traditional fossil fuels owing to its zero carbon emissions, high energy density, fast refueling, compatibility with the existing infrastructure, flexibility, and versatility. Hydrogen use in internal combustion engines signifies a paradigm shift in the engine community toward cleaner and more sustainable transportation solutions. However, challenges such as production costs, distribution infrastructure, and security requirements must be addressed for widespread use. Ongoing research aims to overcome these challenges and enhance the feasibility of using hydrogen as a carbon-free energy source for the engines. This study comprehensively overviews recent research progress and advancements in hydrogen internal combustion engine in terms of the mixture formation mechanism, combustion modes, abnormal combustion mechanism, and the formation mechanism of the nitrogen oxide emissions. In addition, advanced combustion control strategies and technologies have been proposed and summarized to regulate abnormal combustion and nitrogen oxide emissions in the hydrogen engine. The main objectives of this study are to overcome or address these challenges and problems and further enhance the feasibility of hydrogen as a carbon-free alternative fuel for the engine.
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.
期刊：
Proceedings of the IEEE International Conference on Industrial Technology,2024年:1-6 ISSN：2641-0184
作者机构：
[Xingyu Deng; Haifei Chen; Lijun Li] School of Mechanical and Electrical Engineering, Central South University of Forestry and Technology, Changsha, China
会议名称：
2024 IEEE International Conference on Industrial Technology (ICIT)
会议时间：
25 March 2024
会议地点：
Bristol, United Kingdom
会议论文集名称：
2024 IEEE International Conference on Industrial Technology (ICIT)
关键词：
Fixed-time control;Prescribed performance control;Barrier Lyapunov function;Sliding mode control
摘要：
This paper investigates the tracking control problem of robot manipulators with complex uncertainties and proposes an improved fixed-time nonsingular terminal sliding mode performance control (IFTSMPPC) method. Firstly, the barrier Lyapunov function and the prescribed performance function are used to jointly constrain the error state, and the prescribed performance function is used to constrain the transient and steady-state performance of the system. In addition, non singular terminal sliding mode control is incorporated into a fixed time control framework to improve system stability and convergence speed. Finally, the effectiveness and fast convergence of the control scheme were verified through Matlab simulation experiments.
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
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：
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.
