上海工程技术大学学报

Design and optimization of dimethyl ether reforming reactor for hydrogen production

WEI Shiping, LI Cong

2023, 37(4): 335-342. doi: 10.12299/jsues.22-0242

Abstract:
A frustum of a cone for dimethyl ether (DME) steam reforming hydrogen production was designed, and the numerical model of DME steam reforming hydrogen production reaction system was established. The numerical model was solved by COMSOL software, the numerical results of simulation and experiment were basically consistent. By optimizing the structure of the reforming reactor, higher DME conversion rate was obtained. The influence of the cone change on the reforming reaction , and the influence of reaction conditions on DME conversion and hydrogen production were analyzed. The results showed that higher hydrogen yield and thermal efficiency can be obtained When increasing the taper within a certain range. Through structural optimization, the DME steam reforming reaction system can obtain 92.21% DME conversion and 90.54% hydrogen production rate. The highest thermal efficiency is 74.6%.

[Abstract](232) [FullText HTML] (123) [PDF 1614KB](139)

Study on photocatalytic nitrobenzene reduction to aniline over hierarchical flower-like Cu/TiO₂

SUN Honghua, ZHANG Nianchen, SUN Biao, LI Peng, XU Fengxia, WANG Jinguo

2023, 37(4): 343-350. doi: 10.12299/jsues.22-0199

Abstract:
A series of metal Cu-modified hierarchical flower-like TiO₂ catalysts (X% Cu/TiO₂) was prepared by using an alcoholysis solvothermal method, and their photocatalytic performance were evaluated by using visible-light photocatalytic reduction of nitrobenzene to aniline as a model reaction. The results show that 3.3% Cu/TiO₂ photocatalyst exhibits excellent catalytic activity, achieving 83% nitrobenzene conversion under visible-light irradiation for 3.0 h. There are two main attributions : firstly, the hierarchical structure enlarged the catalyst’s surface area and thus, improved the adsorption and diffusion of nitrobenzene and its contact efficiency with catalyst; secondly, the introduction of metal Cu reduced the catalyst’ energy band and enhanced the separation ability of photoelectron-hole, and thus enhanced the photocatalytic activity. In addition, 3.3% Cu/TiO₂ also exhibits good stability and shows good potential in practical applications.

[Abstract](226) [FullText HTML] (78) [PDF 3522KB](35)

Preparation of N-TiO₂ photocatalyst and its degradation of organic pollutants under blue LED light

ZOU Jingtao, LI Xuankun, LI Guanghui, ZHANG Wenqi, SUN Wen

2023, 37(4): 351-358. doi: 10.12299/jsues.22-0190

Abstract:
Nitrogen-doped titanium dioxide (N-TiO₂) photocatalyst was synthesized by mechanochemical, hydrolysis precipitation and sol-gel method respectively. With the application of Methylene blue (MB) and tetraccycline hydrochloride (TTC) as the target pollutants, N-TiO₂-H synthesized by hydrolysis precipitation method has high photocatalysis activity under blue LED irradiation, uniform particle distribution and no agglomeration. Therefore, N-TiO₂-H was selected to study the effects of calcination temperature, catalyst dosage, pH and initial concentration of organic pollutants by photocatalysis. The results showed that N-TiO₂-H calcined at 400 ℃ had the best photocatalytic activity under blue LED light irradiation. Under the dosage of 0.5 g/L N-TiO₂-H, the photocatalytic degradation of MB with initial concentration of 5 mg/L, pH=7, MB removal was 89.7% after 2 h, and the photocatalytic degradation of TTC with initial concentration of 50 mg/L, pH=5, TTC removal was 75.2% after 1.5 h.

[Abstract](148) [FullText HTML] (73) [PDF 2030KB](22)

Output performance of composite tribo-materials based on NiFe₂O₄/BaTiO₃

YAN Yimeng, LI Bin, QI Baoliang, CHEN Jun, JIAO Yuanjing

2023, 37(4): 359-362. doi: 10.12299/jsues.22-0329

Abstract:
Tribo-material is one of the most critical components in triboelectric nanogenerators (TENG). NiFe₂O₄/BaTiO₃ nanoparticles were filled into polydimethylsiloxane (PDMS), and the effects of two inorganic materials as fillers on generator output performance were studied in order to obtain a flexible triboelectric nanogenerator with higher output performance. It was found that both NiFe₂O₄ and BaTiO₃ ceramic particles were polycrystalline and well-crystallized. Both nanoparticles could effectively enhance the electrical output value of PDMS. In particular, the output voltage of NiFe₂O₄/BaTiO₃/PDMS composite film was significantly higher than that of PDMS film. The NiFe₂O₄/BaTiO₃/PDMS composite film with a weight ratio of 7.5∶2.5∶90 possessed the highest output voltage.

[Abstract](191) [FullText HTML] (71) [PDF 1089KB](30)

Study on preparation and tribological properties of PTFE composite lubricant based on uniform design

LAN Yi, GONG Hongying, CUI Zhiwei, XU Peiquan, YAO Zhixin, ZHANG Tao, CHEN Haochuan

2023, 37(4): 363-367. doi: 10.12299/jsues.21-0228

Abstract:
A new type of composite lubricant was prepared and its friction and wear characteristics were studied. The lubricant formula was optimized through the uniform design method, a model was established with SPSS and Matlab softwares, and results were analyzed by Intuitive analysis and regression analysis. The polytetrafluoroethylene (PTFE) was added to prepare a new type of composite lubricant p2, the lubricant contact friction status was analyzed to determine whether the friction coefficient of the contact surface had significantly reduced, and various properties of the metal were further analyzed. The results show that friction coefficients of lubricant p2 added with PTFE have reduced by 51.26% and 29.81% compared with dry friction and lubricant p1 respectively. Observing the morphology of the wear scars, it is found that the friction film can make the metal flow more uniform during the forming process, reduce the deformation force, and effectively avoid a variety of forming defects.

[Abstract](148) [FullText HTML] (81) [PDF 1217KB](353)

Study on droplet characteristics of laser-CMT hybrid welding of aluminum alloy

MA Yubin, LIANG Ying, CI Pengyu, CHEN Feiji

2023, 37(4): 368-371. doi: 10.12299/jsues.22-0331

Abstract:
An aluminum alloy laser-cold metal transfer (CMT) hybrid welding experiment platform and a high-speed camera acquisition platform were established to study the droplet characteristics of aluminum alloy laser-CMT welding process. By changing the laser power, the high speed images of CMT droplet transition under different welding parameters were obtained. Comparative analysis shows that when the laser power is small, the laser mainly plays the role of guiding arc, and has little influence on CMT arc. The welding process is stable and good weld formation can be obtained. When the laser power is large, it will affect the original short circuit transition of CMT, resulting in droplet splashing and other conditions, and lead to poor weld formation. The result shows that keeping the effective distance between the welding wire and the laser and controlling the laser power are the key to ensure the stability of the laser-CMT composite welding process.

[Abstract](280) [FullText HTML] (106) [PDF 3580KB](33)

Intelligent vehicle trajectory tracking control algorithm based on recursive least square

LI Teng, REN Hongjuan

2023, 37(4): 372-379, 408. doi: 10.12299/jsues.22-0209

Abstract:
A novel adaptive lateral optimal tracking control algorithm for real-time estimation of tire lateral stiffness was proposed. The approximate linear range of tire lateral forces were altered with variation in road surface adhesion coefficients, rendering tire lateral stiffness estimations based on linear approximations unreliable. Utilizing the recursive least squares algorithm and taking tire slip angle and lateral force as inputs, the tire's lateral stiffness was estimated in real time and an adaptive linear quadratic regulator (ALQR) controller was developed. The effectiveness and robustness of the algorithm were validated on a joint simulation platform combining Matlab/Simulink and Carsim. The results demonstrated that under various road surface adhesion conditions and at different vehicle speeds, the performance of the designed control algorithm consistently surpassed that of the traditional linear quadratic regulator (LQR) control algorithm. Specifically, the maximum lateral position error and yaw angle error were reduced by 81.5% and 73.0%, respectively. Real-vehicle tests empirically validated the practical applicability and effectiveness of the algorithm, with the maximum trajectory tracking error being only 0.56 m.

[Abstract](193) [FullText HTML] (131) [PDF 3747KB](36)

Generation of grinding area for vehicle surface maintenance based on convex hull algorithm

GENG Fangqi, WU Minghui, WANG Yaqiang, ZHOU Zhifeng, ZHOU Wei

2023, 37(4): 380-386. doi: 10.12299/jsues.23-0069

Abstract:
In a traditional industry, automotive paint repair is dominated by manual labor, which has problems such as high labor intensity, low efficiency and poor consistency. Combining the experience of manual sanding, the algorithm of generating the damaged car surface repair sanding area was designed based on the extraction of the damaged car surface contour. Firstly, the edge detection operator and convex hull algorithm were used to extract the contour of the damaged paint surface, then the convex package algorithm was used to pre-generate the contour, and then the contour was improved to generate the final car surface repair sanding area. By comparing the actual manual sanding area and the algorithm-generated sanding area, it shows that the sanding area generated by the algorithm is more accurate and meets the basic sanding requirements, which can provide a theoretical basis for the realization of automated sanding.

[Abstract](149) [FullText HTML] (74) [PDF 1711KB](34)

Dynamic IGBT thermal management strategy based on real-time junction temperature estimation

YANG Shangming, MA Qihua

2023, 37(4): 387-396. doi: 10.12299/jsues.22-0374

Abstract:
Insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT) is an important energy transfer and conversion component of electric vehicles. But working under varying conditions for a long time will result in high heat loads, which seriously affect IGBT service life. By establishing IGBT junction temperature estimation model for real-time temperature observation, the relationship between IGBT junction temperature, switch frequency and bus voltage was analyzed. In order to reduce the heat load of IGBT under cyclic conditions, the IGBT junction temperature regional control strategy was proposed. Aiming at controlling the maximum junction temperature and the junction temperature fluctuation, the control region was divided, and the switching frequency and bus voltage were controlled by fuzzy control and PI control respectively. The results show that the maximum junction temperature decreases by 5.1 ℃ and the junction temperature fluctuation of IGBT decreases by 2.6 ℃ on average under new European driving cycle (NEDC) condition, which verified the effectiveness of the control strategy and improved the reliability and operation life of IGBT.

[Abstract](420) [FullText HTML] (94) [PDF 2576KB](40)

AGV scheduling for order-driven intelligent workshop based on reinforcement learning

WEI Chengkun, ZHOU Jun

2023, 37(4): 397-403. doi: 10.12299/jsues.22-0334

Abstract:
Material transporting efficiency has an important impact on the production scheduling efficiency of the intelligent workshop. Material transporting tasks are usually executed by automated guided vehicle (AGV), which have large number of tasks, real-time changes in task demand, and intensive task issuance. In order to make the AGV workflow timely, efficient and accurate, an reinforcement-learning-based AGVs' scheduling model was established with a two-level mechanism. The first level aimes for load balancing, and assigns the tasks to AGVs in a rule-based scheduling method. The second level plans each AGV's path by a reinforcement learning deep Q-network (DQN) algorithm with single agent, which can reduce the convergence difficulty of the scheduling algorithm by reducing the dimensions of the agent's action space. The effectiveness and innovation of the method was verified through simulation examples.

[Abstract](418) [FullText HTML] (112) [PDF 1372KB](35)

Investigations on extrusion gear of feed mechanism of fused deposition 3D printer

GUO Genqing, WANG Keyong

2023, 37(4): 404-408. doi: 10.12299/jsues.22-0287

Abstract:
As one of the core components of the fused deposition 3D printer, the feed mechanism is responsible for feeding the filaments into the nozzle and completing the printing. The extrusion gear is the key part of the entire feed mechanism. When the whole machine is working, the extrusion gear is in direct contact with the filaments, and the filaments are fed into the nozzle by friction. The tooth shape and number of teeth of the extrusion gears are studied by means of experiments, and the feed rate in the printing process and the quality of the printed parts are mainly analyzed. The results show that the extrusion efficiency of the helical extrusion gear is higher than that of the straight and concave teeth, but the phenomenon of tooth skipping occurs at a high speed. When working, the more teeth of the extrusion gear, the closer the actual feed is to the theoretical value.

[Abstract](251) [FullText HTML] (90) [PDF 994KB](22)

Reversible logic synthesis algorithmbased on cooperative multi-objective differential evolution

WANG Xu

2023, 37(4): 409-413. doi: 10.12299/jsues.23-0047

Abstract:
Reversible logic circuits can avoid thermal dissipation due to information loss so that it is possible to solve the thermal dissipation problem of integrated circuits. As reversible logic circuit synthesis problem was modeled as a multi-objective optimization problem, a reversible logic synthesis method was proposed based on a cooperative multi-objective differential evolution algorithm. Differential evolution algorithm with self-adaptive population resizing mechanism (SapsDE) was adopted as the basis and combined with the co-evolution algorithm based multiple population strategy for multiple objectives. Meanwhile, the population updating scheme and the fitness evaluation strategy based on Pareto-optimal were employed to update the candidate individuals. The synthesis method tested on a suite of benchmark functions is feasible and effective. Compared with classical and heuristic synthesis methods, the circuits generated by the proposed synthesis method have better performance.

[Abstract](122) [FullText HTML] (77) [PDF 691KB](35)

Registration method for grid point cloud based on improved FPFH

ZHANG Ruxiao, FANG Yu, YANG Hao, HANG Guanrong, TAO Hanzhong, NING Yeyan

2023, 37(4): 414-419. doi: 10.12299/jsues.21-0086

Abstract:
An improved fast point feature histogram (FPFH) was proposed for the initial registration of grid point cloud. The neighborhood density was added as a point feature description on the basis of FPFH. When searching the corresponding points with k-dimensional tree (k-d tree), the Bhattacharyya distance was used as the index. This improved method was compared with FPFH in the simulation. Then, the test device was built to collect the grid’s surface point cloud data. The data were registered with improved FPFH method and iterative closest point (ICP). Test results show that the precision level of the matched point cloud is 1 μm and the error range of grid hole stays in ±(20~40) μm, which theoretically satisfy the precision requirement of the grid.

[Abstract](209) [FullText HTML] (256) [PDF 1310KB](425)

Method for recognizing and locating for multi-target stone based on intelligent breaker operation scenario

WANG Wenchao, MA Qihua, ZHAO Lei

2023, 37(4): 420-427. doi: 10.12299/jsues.22-0313

Abstract:
With the continuous development of intelligent construction machinery, the traditional hydraulic breaker with complex structure and single function has been gradually replaced by the increasingly mature intelligent breaker. The recognition and localization of multi-target stones is an important guarantee for intelligent crushing to improve the accuracy of action output and complete the crushing task. A target stone recognition and localization method based on segmentation-mask convolutional neural networks (Mask R-CNN) instance segmentation and light detection and ranging (LiDAR) information fusion was proposed. The Mask R-CNN instance segmentation algorithm was used to quickly identify the region of interest (RoI) of the target stone in complex operation scenarios. On the premise of ensuring the accuracy of stone detection, the position information of the crushing point was obtained by fusing lidar and the Kalman filter algorithm to guide the crushing hammer to realize the positioning operation. The results of the field tests show that the average recognition accuracy of the stone target detection model for stones is 95.35%, the recall rate is 95.06%, and the accuracy of stone breaking point recognition is 94.20%, can meet the real-time requirements.

[Abstract](215) [FullText HTML] (101) [PDF 1773KB](44)

Research and prospect of margin trading in China based on knowledge graph analysis

YANG Hailing, SHI Xingsen, XIAO Huihui, WANG Guoqiang

2023, 37(4): 428-434. doi: 10.12299/jsues.22-0337

Abstract:
Based on the 411 key research papers published in CNKI database from 1994 to 2021, the published works, research institutions and research strengths, journal sources, high frequency co-cited literature and classical literature contents in the field of margin trading in China were systematically analyzed. Employing the CiteSpace software to draw a knowledge map, the evolution process, research frontiers and trends of domestic margin trading research hotspots were summarized. The results show that the overall number of research papers and their cyclical fluctuation in the domestic margin trading field are subject to the expansion policies. Fudan University, Nanjing University, etc. as the main research institutions had made the biggest contributions; researches concerning the stock price volatility and pricing efficiency by Chu Jian, Li Zhisheng and other scholars had become high frequency cited results in this field. The research process in the field of margin trading were divided into five stages: germination, start, landing, development and maturity. The research hotspots were mainly concentrated on five aspects: market impacts relationship, corporate decision-making and management, stakeholder influence, R&D investment relationship and business theory improvement, which can provide a frame of reference for scholars studying margin trading business.

[Abstract](426) [FullText HTML] (125) [PDF 2046KB](44)

2023 Vol. 37, No. 4