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Near infrared emissions from both high efficient quantum cutting (173%) and nearly-pure-color upconversion in NaY(WO_(4))_(2):Er^(3+)/Yb^(3+) with thermal management capability for silicon-based solar cells

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Light(Science & Applications) 2024年第1期13卷 113-126页

作者： Duan Gao Baojiu Chen Xuezhu Sha Yuhang Zhang Xin Chen Li Wang Xizhen Zhang Jinsu Zhang Yongze Cao Yichao Wang Lei Li Xiangping Li Sai Xu Hongquan Yu Lihong Cheng School of Science Dalian Maritime UniversityDalian 116026 LiaoningChina

Raising photoelectric conversion efficiency and enhancing heat management are two critical concerns for siliconbased solar *** this work,efficient Yb^(3+) infrared emissions from both quantum cutting and upconversion were demonstrated by adjusting Er^(3+) and Yb^(3+) concentrations,and thermo-manage-applicable temperature sensing based on the luminescence intensity ratio of two super-low thermal quenching levels was discovered in an Er^(3+)/Yb^(3+) codoped tungstate *** quantum cutting mechanism was clearly decrypted as a two-step energy transfer process from Er^(3+) to Yb^(3+).The two-step energy transfer efficiencies,the radiative and nonradiative transition rates of all interested 4 f levels of Er^(3+) in NaY(WO_(4))_(2) were confirmed in the framework of Föster-Dexter theory,Judd-Ofelt theory,and energy gap law,and based on these obtained efficiencies and rates the quantum cutting efficiency was furthermore determined to be as high as 173%in NaY(WO_(4))_(2):5 mol%Er^(3+)/50 mol%Yb^(3+) *** and nearly pure infrared upconversion emission of Yb3+under 1550 nm excitation was achieved in Er^(3+)/Yb^(3+)co-doped NaY(WO_(4))_(2) by adjusting Yb^(3+) doping *** Yb^(3+) induced infrared upconversion emission enhancement was attributed to the efficient energy transfer ^(4)I_(11/2)(Er^(3+))+^(2)F_(7/2)(Yb^(3+))→^(4)I_(15/2)(Er^(3+))+^(2)F_(5/2)(Yb^(3+))and large nonradiative relaxation rate of ^(4)I_(9/2).Analysis on the temperature sensing indicated that the NaY(WO_(4))_(2):Er^(3+)/Yb^(3+)serves well the solar cells as thermos-managing ***,it was confirmed that the fluorescence thermal quenching of ^(2)H_(11/2)/^(4)S_(3/2) was caused by the nonradiative relaxation of ^(4)S_(3/2).All the obtained results suggest that NaY(WO_(4))_(2):Er^(3+)/Yb^(3+) is an excellent material for silicon-based solar cells to improve photoelectric conversion efficiency and thermal management.

关键词： quantum thermal relaxation

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Influence of acceleration stage electrode voltage on the performance of double-stage Hall effect thruster with adjustable zero magnetic point

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Plasma Science and Technology 2024年第6期26卷 60-69页

作者：陈龙高维富崔作君段萍许雪松阚子晨檀聪琦陈俊宇 School of Science Dalian Maritime UniversityDalian 116026People’s Republic of China

The configuration of electrode voltage and zero magnetic point position has a significant impact on the performance of the double-stage Hall effect thruster. A 2D-3V model is established based on the two-magnetic peak type double-stage Hall thruster configuration, and a particle-in-cell simulation is carried out to investigate the influences of both acceleration electrode voltage value and zero magnetic point position on the thruster discharge characteristics and *** results indicate that increasing the acceleration voltage leads to a larger potential drop in the acceleration stage, allowing ions to gain higher energy, while electrons are easily absorbed by the intermediate electrode, resulting in a decrease in the anode current and ionization rate. When the acceleration voltage reaches 500 V, the thrust and efficiency are maximized, resulting in a 15%increase in efficiency. After the acceleration voltage exceeds 500 V, a potential barrier forms within the channel, leading to a decrease in thruster efficiency. Further study shows that as the second zero magnetic point moves towards the outlet of the channel, more electrons easily traverse the zero magnetic field region, participating in the ionization. The increase in the ionization rate leads to a gradual enhancement in both thrust and efficiency.

关键词： Hall thruster particle-in-cell simulation intermediate electrode zero magnetic point

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Effect of ion stress on properties of magnetized plasma sheath

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Plasma Science and Technology 2024年第2期26卷 1-12页

作者：陈龙崔作君高维富段萍阚子晨檀聪琦陈俊宇 School of Science Dalian Maritime UniversityDalian 116026People's Republic of China

In the plasma sheath, there is a significant gradient in ion velocity, resulting in strong stress on ions treated as a fluid. This aspect has often been neglected in previous sheath studies. This study is based on the Braginskii plasma transport theory and establishes a 1D3V sheath fluid model that takes into account the ion stress effect. Under the assumption that ions undergo both electric and diamagnetic drift in the presheath region, self-consistent boundary conditions,including the ion Bohm velocity, are derived based on the property of the Sagdeev ***, assuming that the electron velocity at the wall follows a truncated Maxwell distribution, the wall floating potential is calculated, leading to a more accurate sheath thickness estimation. The results show that ion stress significantly reduces the sheath thickness, enhances ion Bohm velocity, wall floating potential, and ion flux at the wall. It hinders the acceleration of ions within the sheath, leading to notable alterations in the particle density profiles within the sheath. Further research indicates that in ion stress, bulk viscous stress has the greatest impact on sheath properties.

关键词： magnetized plasma sheath ion stress Bohm criterion

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Molecular dynamics simulation of the flow mechanism of shear-thinning fluids in a microchannel

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Chinese Physics B 2024年第4期33卷 516-525页

作者：杨刚郑庭程启昊张会臣 Naval Architecture and Ocean Engineering College Dalian Maritime UniversityDalian 116026China

Shear-thinning fluids have been widely used in microfluidic systems,but their internal flow mechanism is still ***,in this paper,molecular dynamics simulations are used to study the laminar flow of shear-thinning fluid in a *** validated the feasibility of our simulation method by evaluating the mean square displacement and Reynolds number of the solution *** results show that the change rule of the fluid system's velocity profile and interaction energy can reflect the shear-thinning characteristics of the *** velocity profile resembles a top-hat shape,intensifying as the fluid's power law index *** interaction energy between the wall and the fluid decreases gradually with increasing velocity,and a high concentration of non-Newtonian fluid reaches a plateau ***,the velocity profile of the fluid is related to the molecule number density distribution and their values are inversely *** analyzing the radial distribution function,we found that the hydrogen bonds between solute and water molecules weaken with the increase in *** observation offers an explanation for the shear-thinning phenomenon of the non-Newtonian flow from a micro perspective.

关键词： molecular dynamics simulation non-Newtonian fluid microchannel shear-thinning

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Long Duration Coverage Control of Multiple Robotic Surface Vehicles Under Battery Energy Constraints

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IEEE/CAA Journal of Automatica Sinica 2024年第7期11卷 1695-1698页

作者： Shengnan Gao Zhouhua Peng Haoliang Wang Lu Liu Dan Wang the School of Electrical and Control Engineering North China University of TechnologyBeijing 100144 the School of Marine Electrical Engineering Dalian Maritime UniversityDalian 116026China State Key Laboratory of Maritime Technology and Safety Dalian 116026 Dalian Key Laboratory of Swarm Control and Electrical Technology for Intelligent Ships Dalian 116026 the School of Marine Engineering Dalian Maritime UniversityDalian 116026

Dear Editor,This letter addresses long duration coverage problem of multiple robotic surface vehicles(RSVs) subject to battery energy constraints,in addition to uncertainties and disturbances. An anti-disturbance energy-aware control method is proposed for performing coverage task of RSVs. Firstly, a centroidal Voronoi tessellation(CVT) is used to optimize the partition of the given coverage area.

关键词： Robotic Battery partition

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Highly adaptive triboelectric tactile sensor on the foot of autonomous wall-climbing robots for detecting the adhesion state and avoiding the hazard

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Nano Research 2024年第7期17卷 6518-6526页

作者： Zhaoyang Wang Jianhua Liu Ziyu Wang Chang Liu Qingyu Chen Chaofan Zhang Wenbo Zhang Jicang Si Xiu Xiao Peng Xu Minyi Xu Dalian Key Lab of Marine Micro/Nano Energy and Self-powered System Marine Engineering CollegeDalian Maritime UniversityDalian 116026China Information Science and Technology College Dalian Maritime UniversityDalian 116026China Navigation College Dalian Maritime UniversityDalian 116026China Intelligent Biomimetic Design Lab College of EngineeringPeking UniversityBeijing 100871China

Due to the excellent maneuverability and obstacle crossing of legged robots,it is possible for an autonomous legged wallclimbing robots to replace manual inspection of ship exterior ***,when the magnetic adsorption legged wallclimbing robot steps on the convex point or convex line of the wall,or even when the robot missteps,the robot is likely to detach from the ferromagnetic ***,this paper proposes a tactile sensor for the legged magnetic adsorption wall-climbing robot to detect the magnetic adsorption state and improve the safety of the autonomous crawling of the *** tactile sensor mainly comprises a three-dimensional(3D)-printed shell,a tactile slider,and three isometric sensing units,with an optimized *** experiment shows that the triboelectric tactile sensor can monitor the sliding depth of the tactile slider and control the light-emitting device(LED)signal *** addition,in the demonstration experiment of detecting the adsorption state of the robot's foot,the triboelectric tactile sensor has strong adaptability to various ferromagnetic wall ***,this study establishes a robot gait control system to verify the feedback control ability of the triboelectric tactile *** results show that the robot equipped with the triboelectric tactile sensor can recognize the dangerous area on the crawling wall and autonomously avoid the ***,the proposed triboelectric tactile sensor has great potential in realizing the tactile sensing ability of robots and enhancing the safety and intelligent inspection of ultra-large vessels.

关键词： legged wall-climbing robot ship inspection tactile perception triboelectric sensor

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Assessing Dietary Consumption of Sodium and Potassium in China through Wastewater Analysis

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Biomedical and Environmental Sciences 2024年第1期37卷 127-131页

作者： TAN Dong Qin LIANG Yi GUO Ting LI Yan Ying SONG Yong Xin WANG De Gao College of Environmental Science and Engineering Dalian Maritime UniversityDalian 116026LiaoningChina College of Marine Engineering Dalian Maritime UniversityDalian 116026LiaoningChina

A causal relationship has been reported between the average population salt(sodium chloride)intake and the increased risk of stroke and cardiovascular and cerebrovascular diseases in some epidemiological and clinical *** World Health Organization has recommended that a sodium intake of<2 g/day is preventive against cardiovascular disease,although the current intake is in excess in most countries.

关键词： Wastewater intake Potassium

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动力定位船舶鲁棒自适应异步自触发控制

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哈尔滨工程大学学报 2024年第7期45卷 1376-1383页

作者：姚明启张国庆宋纯羽张显库大连海事大学航海学院辽宁大连 116026

针对动力定位船舶的通信带宽受限、执行器增益不确定性等问题,本文提出了一种异步自触发动力定位控制策略.该策略设计了一种自触发机制,解决了传统事件触发方法需要对触发条件进行连续监控这一约束,即下一触发时刻仅需要根据当前时刻的... 详细信息

针对动力定位船舶的通信带宽受限、执行器增益不确定性等问题,本文提出了一种异步自触发动力定位控制策略.该策略设计了一种自触发机制,解决了传统事件触发方法需要对触发条件进行连续监控这一约束,即下一触发时刻仅需要根据当前时刻的相关信息进行计算.对于具有多个执行器的动力定位船舶,每个执行器的自触发机制相互独立互不影响,即其每个控制器-执行器信道中的控制信号均为异步触发式传输.此外,对于每个执行器设计了一个自适应参数对其增益不确定性进行在线估计和补偿.通过仿真实验对上述控制策略进行验证,仿真结果表明:所提出算法具有较高的定位精度与稳定性能,且极大程度上减少了控制信号的传输次数,相较于对比算法减少了 100 倍传输次数,具有低通信负载的优点,更加符合工程需求.

关键词：动力定位自触发控制增益不确定自适应控制鲁棒控制神经网络反步法非线性控制

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Path-Following Control With Obstacle Avoidance of Autonomous Surface Vehicles Subject to Actuator Faults

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 956-964页

作者： Li-Ying Hao Gege Dong Tieshan Li Zhouhua Peng the School of Marine Electrical Engineering Dalian Maritime UniversityDalian 116026China the School of Automation Engineering University of Electronic Science and Technology of ChinaChengdu 611731the Navigation CollegeDalian Maritime UniversityDalian 116026 the Yangtze Delta Region Institute(Huzhou) Huzhou 313001China

This paper investigates the path-following control problem with obstacle avoidance of autonomous surface vehicles in the presence of actuator faults,uncertainty and external *** surface vehicles inevitably suffer from actuator faults in complex sea environments,which may cause existing obstacle avoidance strategies to *** reduce the influence of actuator faults,an improved artificial potential function is constructed by introducing the lower bound of actuator efficiency *** nonlinear state observer,which only depends on measurable position information of the autonomous surface vehicle,is used to address uncertainties and external *** using a backstepping technique and adaptive mechanism,a path-following control strategy with obstacle avoidance and fault tolerance is designed which can ensure that the tracking errors converge to a small neighborhood of *** with existing results,the proposed control strategy has the capability of obstacle avoidance and fault tolerance ***,the comparison results through simulations are given to verify the effectiveness of the proposed method.

关键词： Actuator faults autonomous surface vehicle(ASVs) improved artificial potential function nonlinear state observer obstacle avoidance

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Highly adaptive and broadband triboelectric energy harvester with stretching silicone rubber strip for variable harmonic frequency vibration

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Nano Research 2024年第5期17卷 4089-4099页

作者： Taili Du Dianlong Shen Ziyue Xi Hongyong Yu Fangyang Dong Cong Zhao Meixian Zhu Yongjiu Zou Peiting Sun Minyi Xu Dalian Key Laboratory of Marine Micro/Nano Energy and Self-powered Systems Marine Engineering CollegeDalian Maritime UniversityDalian 116026China Collaborative Innovation Research Institute of Autonomous Ship Dalian Maritime UniversityDalian 116026China

An enormous number of wireless sensing nodes(WSNs)are of great significance for the Internet of Things(IoT).It is tremendously prospective to realize the in-situ power supply of WSNs by harvesting unutilized mechanical vibration energy.A harmonic silicone rubber triboelectric nanogenerator(HSR-TENG)is developed focusing on ubiquitous constant working frequency *** unique design of the strip serving as a flexible resonator realizes both soft contact and high and broadband *** significant factors influencing the 1^(st)-order vibration mode of the strip are developed for realizing the harmonic frequency adaptation to external *** surface treatment of the strip improves the output performance of HSR-TENG by 49.1%as well as eliminates the adhesion *** HSR-TENG is able to achieve a voltage output bandwidth of 19 Hz under a vibration strength of 3.0,showing its broadband *** peak power density of 153.9 W/m^(3)is achieved and 12×0.5 W light-emitting diodes(LEDs)are successfully illuminated by the *** can continuously power a temperature sensor by harvesting the actual compressor vibration *** brief,the HSR-TENG provides a promising way for constant frequency vibration energy harvesting,so as to achieve in-situ power supply for the WSNs in the vicinity.

关键词： vibration energy harvesting triboelectric nanogenerator flexible silicone rubber strip harmonic vibration broadband

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