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Dynamic Scheduling and Path Planning of Automated Guided Vehicles in Automatic Container Terminal

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IEEE/CAA Journal of Automatica Sinica 2022年第11期9卷 2005-2019页

作者： Lijun Yue Houming Fan the Department of Transportation Engineering Dalian Maritime UniversityDalian 116026China

The uninterrupted operation of the quay crane(QC)ensures that the large container ship can depart port within laytime,which effectively reduces the handling cost for the container terminal and ship *** QC waiting caused by automated guided vehicles(AGVs)delay in the uncertain environment can be alleviated by dynamic scheduling optimization.A dynamic scheduling process is introduced in this paper to solve the AGV scheduling and path planning problems,in which the scheduling scheme determines the starting and ending nodes of paths,and the choice of paths between nodes affects the scheduling of subsequent *** work proposes a two-stage mixed integer optimization model to minimize the transportation cost of AGVs under the constraint of laytime.A dynamic optimization algorithm,including the improved rule-based heuristic algorithm and the integration of the Dijkstra algorithm and the Q-Learning algorithm,is designed to solve the optimal AGV scheduling and path schemes.A new conflict avoidance strategy based on graph theory is also proposed to reduce the probability of path conflicts between *** experiments are conducted to demonstrate the effectiveness of the proposed model and algorithm over existing methods.

关键词： Automated container terminal dynamic scheduling path planning Q-Learning algorithm rule-based heuristic algorithm

Effect of tip geometry and tip clearance on aerodynamic performance of a linear compressor cascade

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Chinese Journal of Aeronautics 2013年第3期26卷 583-593页

作者： Zhong Jingjun Han Shaobing Lu Huawei Kan Xiaoxu Marine Engineering College Dalian Maritime University

The tip leakage flow between a blade and a casing wall has a strong impact on compressor pressure rise capability, efficiency, and stability. Consequently, there is a strong motivation to look for means to minimize its impact on performance. This paper presents the potential of passive tip leakage flow control to increase the aerodynamic performance of highly loaded compressor blades. Experimental investigations on a linear compressor cascade equipped with blade winglets mounted to the blade tips have been carried out. Results for a variation of the tip clearance and the winglet geometry are presented. Current results indicate that the use of proper tip winglets in a compressor cascade can positively affect the local aerodynamic field by weakening the tip leakage vortex. Results also show that the suction-side winglets are aerodynamically superior to the pressure-side or combined winglets. The suction-side winglets are capable of reducing the exit total pressure loss associated with the tip leakage flow and the passage secondary flow to a significant degree.

关键词： Compressor cascade Experimental investigation Tip clearance Tip geometry Tip leakage vortex

Upconversion luminescence of Y2Ti2O7：Er3＋ under 1550 and 980 nm excitation

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Journal of Rare Earths 2017年第3期35卷 230-234页

作者：殷秀梅汪红邢明铭付姚田莹沈显良于伟光罗昔贤 Physics Department Dalian Maritime University Dalian 116026 China

Er^（3＋） doped Y_2Ti_2O_7 phosphors were prepared by the high temperature solid state reaction method at 1500℃.X-ray diffraction and luminescence spectra were used to characterize the properties of *** to the layer distribution of Y^（3＋） ions in the pyrochlore Y_2Ti_2O_7 crystal,Er^（3＋） ions,replacing Y^（3＋） in Y_2Ti_2O_7 crystal,could realize high-concentration doping by suppressing energy migration between layers to minimize concentration *** on the upconversion characteristic of Y_2Ti_2O_7：Er^（3＋）showed that the optimal doping concentration of Er^（3＋） was up to 28 mol.%.Y_2Ti_2O_7：0.28 Er^（3＋） exhibited both dominating red emission under 980 and 1550 nm *** brightness of Y_2Ti_2O_7：0.28Er^（3＋） were 4 times（980 nm） and 7 times（1550 nm） higher than that of Y_2Ti_2O_7：0.05Er^（3＋）.And Y_2Ti_2O_7：Er^（3＋） presented much better red emission color purity and stability under 1550 nm excitation.

关键词： upconversion luminescence Y2Ti2O7:Er3+ 1550 nm rare earths

Effects of the Nozzle Design on the Properties of Plasma Jet and Formation of YSZ Coatings under Low Pressure Conditions

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Chinese Journal of Mechanical Engineering 2016年第5期29卷 954-961页

作者： SUN Chengqi GAO Yang YANG Deming FU Yingqing College of Material Science and Engineering Dalian Maritime University Key Laboratory of Ship-Machinery Maintenance & Manufacture Dalian Maritime University

How to control the quality of the coatings has become a major problem during the plasma spraying. Because nozzle contour has a great influence on the characteristic of the plasma jet, two kinds of plasma torches equipped with a standard cylindrical nozzle and a converging-diverging nozzle are designed for low pressure plasma spraying（LPPS） and very low pressure plasma spraying（VLPPS）. Yttria stabilized zirconia（YSZ） coatings are obtained in the reducing pressure environment. The properties of the plasma jet without or with powder injection are analyzed by optical emission spectroscopy, and the electron temperature is calculated based on the ratio of the relative intensity of two Arlspectral lines. The results show that some of the YSZ powder can be vaporized in the low pressure enlarged plasma jet, and the long anode nozzle may improve the characteristics of the plasma jet. The coatings deposited by LPPS are mainly composed of the equiaxed grains and while the unmelted powder particles and large scalar pores appear in the coatings made by VLPPS. The long anode nozzle could improve the melting of the powders and deposition efficiency, and enhance the coatings＇ hardness. At the same time, the long anode nozzle could lead to a decrease in the overspray phenomenon. Through the comparison of the two different size＇s nozzle, the long anode is much more suitable for making the YSZ coatings.

关键词： plasma torch yttria stabilized zirconia electron temperature equiaxed grain thermal barrier coatings

Experimental Studies on Elimination of Microbial Contamination by Hydroxyl Radicals Produced by Strong Ionization Discharge

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Plasma Science and Technology 2008年第4期10卷 463-465页

作者：白敏冬张芝涛赵董艳杨波 Department of Physics Dalian Maritime UniversityDalian 116026China

Using fogdrops of OH^· radicals to eliminate microbial contamination is an effective way to solve the current domestic and international problem. The results show that the threshold of OH solution used in the experiment is 0.6 mg/L, the lethal time is 1 s, and the spray density of OH solution is 21 μL/m^2. The experimental results show that the OH radical possesses the following advantages： celerity, low lethal concentration and spray density, short lethal time, and absence of secondary pollution.

关键词： microbial contamination OH^· radical elimination technology

Preparation and stabilization of γ-La_2S_3 at low temperature

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Journal of Rare Earths 2011年第4期29卷 313-316页

作者：罗昔贤张明马禄彬彭勇 Physics Department Dalian Maritime University

Eu doped γ-La2S3 were synthesized by the sulfurization of their oxide powders using CS2 gas at 700 ℃. During the sulfurizing reaction process, the cubic Eu3S4 crystals of prior formation acted as the nuclei sites of the γ-La2S3 phase to facilitate the nucleation process. The γ-La2S3 transformation occurred at significantly lower temperature by the combined contributions of low transformation enthalpy and induced multiple nuclei. On the other hand, the doped Eu ions could be inserted into the empty tetrahedral S4 cavities to stabilize the γ-La2S3 phase at temperature excess of 1100 ℃.

关键词： rare earth sesquisulfide rare earth sulfide La2S3 crystal growth

Characteristics of DBD micro-discharge at different pressure and its effect on the performance of oxygen plasma reactor

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Plasma Science and Technology 2019年第5期21卷 5-13页

作者： Rui LIU Zhe YU Huijuan CAO Pu LIU Zhitao ZHANG College of Science Dalian Maritime UniversityDalian 116026People's Republic of China Institute of Marine Engineering Dalian Maritime UniversityDalian 116026People's Republic of China

The oxygen plasma reactor based on dielectric barrier discharge principle can produce a high concentration of reactive oxygen species,which can cooperate with hydraulic cavitation gas-liquid mixer to realize the application of advanced oxidation technology in water *** this technology,the work pressure of the oxygen plasma reactor is decreased by the vacuum suction effect generated in the snap-back section of the gas-liquid mixed *** this paper,the characteristics of single micro-discharge at different pressures were investigated with the methods of discharge image,electrical characteristics and spectral diagnosis,in order to analyze the electrical characteristics and reactive oxygen species generation efficiency of oxygen plasma reactor at the pressure range from 60 kPa to 100 *** study indicated that,when the pressure decreases,the duty ratio of ionization in the discharge gap and number of electrons with high energy increases,leading to a rise in reactive oxygen species *** the oxygen reaches the maximum ionization,the concentration of reactive oxygen species is the ***,the discharge intensity continues to increase,producing more heat,which will decompose the ozone and lower the production of reactive oxygen *** oxygen plasma reactor has an optimum working pressure at different input powers,which makes the oxygen plasma reactor the most efficient in generating reactive oxygen species.

关键词： atmospheric pressure plasma reactor pressure active oxygen particle dielectric barrier discharge

Experimental optimum design and luminescence properties of NaY(Gd)(MoO_4)_2:Er^(3+)phosphors

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Chinese Physics B 2016年第6期25卷 201-205页

作者：孙佳石徐赛李树伟石琳琳翟梓会陈宝玖 Department of Physics Dalian Maritime University

Three-factor orthogonal design（OD） of Er3＋/Gd3＋/T（calcination temperature） is used to optimize the luminescent intensity of Na Y（Gd）（MoO4）2：Er3＋***,the uniform design（UD） is introduced to explore the doping concentration range of Er3＋/Gd3＋.Then OD and range analysis are performed based on the results of UD to obtain the primary and secondary sequence and the best combination of Er3＋,Gd3＋,and T within the experimental *** optimum sample is prepared by the high temperature solid state *** excitation and emission spectra of the optimum sample are *** intense green emissions（530 nm and 550 nm） are observed which originate from Er3＋2H11/2→4I15/2and4S3/2→4I15/2,*** effect is investigated in the optimum NaY（Gd3＋）（MoO4）2：Er3＋phosphors,and the green emission intensity decreases as temperature increases.

关键词： orthogonal design(OD) uniform design(UD) NaY(Gd)(MoO4)2 Er3+ luminescent intensity

Effect of Vane Opening on Aerodynamic Performance of the Ram-rotor Test System

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Journal of Thermal Science 2016年第3期25卷 207-215页

作者： HAN Ji-ang GUAN Jian ZHONG Jingjun YUAN Chenguang Marine Engineering College Dalian Maritime University

In order to research the influence of adjustable vane on the aerodynamic performance of the ram-rotor test system, FLUENT soft-ware has been adopted to simulate the flow passage of the ram-rotor test system numerically. The vane opening is controlled by changing the stagger angle of the vane blades. Results show that flow uniformity of vane outlet is influenced by the vane openings, which has an impact on the aerodynamic loss to some extent. Total pressure ratio, adiabatic efficiency and mass flow rate can be regulated by different openings of the vane. Compared with -8° vane opening, top efficiency of the ram-rotor increases by about 13.8% at ＋6° opening. And total pressure ratio drops by 5.87%. The rising opening increases the relative Mach number at inlet of the ram-rotor and weakens the intensity of the tip clearance leakage, which comes to a decreasing aerodynamic loss.

关键词： adjustable vane ram-rotor test system aerodynamic performance numerical simulation