上海工程技术大学学报

Hybrid Fundamental-Solution-Based FEM for Heat Conduction Problems in Orthotropic Materials

QIU Wenkai, WANG Keyong

2020, 34(4): 305-313.

Abstract:
A heat conduction analysis of two-dimensional orthotropic materials was carried out by the hybrid fundamental-solution-based finite element method (HFS-FEM). Temperature distributions within the element domain and on the element boundary were independently described by two temperature fields. A linear combination of fundamental solutions was utilized to approximate the intra-element temperature field while standard one-dimensional shape functions were employed to define the frame temperature field. By virtue of the modified variational functional and divergence theorem, the resultant finite element formulation was derived. The effectiveness of the proposed method was verified by comparing two numerical examples with ABAQUS result. The numerical results demonstrate that the proposed method can still keep excellent accuracy even when the element shape degenerates to a situation of extreme distortion. This is one of marked features which differs from conventional finite element methods.

[Abstract](376) [FullText HTML] (332) [PDF 1634KB](192)

Surface Morphology Control and Surface Enhanced Raman Scattering Effect of GO/Au/Ag Composite

WANG Qinsheng, YANG Yongqiang, WANG Ling, ZHANG Yan

2020, 34(4): 314-319.

Abstract:
Surface enhanced Raman scattering (SERS) has attracted much attentions in the field of chemical detection because of its high sensitivity and nondestructive detection. Graphene oxide/Au/Ag (GO/Au/Ag) composites were prepared by in-situ chemical reduction method. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and Ultraviolet-visible spctrophotometer (UV) were used to characterize the structure of the composites, and the effect of Au/Ag ratio on the morphology and SERS of composites were strudied. Rhodamine 6G (R6G) was used as the probe molecule to study the influence of composites morpfology on surface enhanced SERS. The result show that GO/Au/Ag composites have good SERS enhanced effect, and the SERS signal intensity is related to the surface morphology and the content (mass fraction) of Au and Ag. The increase of surface roughness of Au/Ag particles and the content of Au and Ag could significantly increased the SERS effect of GO/Au/Ag composites.

[Abstract](226) [FullText HTML] (175) [PDF 1170KB](167)

Research on Microstructure and Properties of TaC/FeCoCrNiTiMo Cladding Layer Prepared by Laser Cladding

HUANG Jinpei, LI Zhongwen, ZHANG Qi, YU Zhishui

2020, 34(4): 320-323.

Abstract:
The cladding layer of FeCoCrNiTiMo high entropy alloy with TaC nanoparticle was prepared on the surface of 45# steel by laser cladding. The phase composition, microstructure and the cross-section hardness of the cladding layer were analyzed and tested by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and microhardness tester. Studies show that by adding TaC nanoparticles to FeCoCrNiTiMo high entropy alloy cladding layer, the phase structure of the alloy is mainly composed of body-centered cubic FeCrNi solid solution and face-centered cubic NiCrCoMo solid solution, and contains a very small amount of intermetallic compounds. The Vickers hardness (HV) of cladding layer reaches 1058.89, which is twice the hardness of the base material.

[Abstract](253) [FullText HTML] (217) [PDF 874KB](162)

Research Progress of Inorganic Nano-Catalyst for Chemodynamic Therapy

BAI Xin, ZHANG Mingyi, ZHENG Nannan, WANG Jinxia, ZHAO Hang, GUAN Shaoqi, WANG Xingyan, LU Jie, LIU Xijian

2020, 34(4): 324-330.

Abstract:
Chemodynamic therapy (CDT) is a minimally aggressive emerging cancer treatment, which introduces nanocatalysts into cancer treatment to promote the production of specific toxic reactive oxygen species (ROS) in tumors, inducing the death of tumor cells. Summaried from the aspects of the mechanism of CDT, the choice of nanocatalytic materials, and combinations of CDT with photothermal therapy, chemotherapy, photodynamic therapy and radiotherapy to improve the efficiency of tumor treatment, it indicates that the CDT is expected to become an alternative method of tumor treatment.

[Abstract](310) [FullText HTML] (264) [PDF 10561KB](113)

Effect of Copper and Nickel Ions on Aerobic Granular Sludge Treatment and Improvement Strategy

LIU Xinyue, GAO Feng, SHU Shihu

2020, 34(4): 331-336.

Abstract:
Aerobic granular sludge has become one of the mainstream methods for the treatment of printing and dyeing wastewater due to its rich microbial biomass and strong impact resistance. However, the presence of Cu²⁺ and Ni²⁺ in the printing and dyeing wastewater will have various effects on the aerobic granular sludge treatment process, which will reduce the treatment effect of aerobic granular sludge. Based on the literature review, the effects of Cu²⁺ and Ni²⁺ on the microbial population distribution of aerobic granular sludge, sludge flocculation and sedimentation, and reaction kinetics were analyzed. According to the different effects of Cu²⁺ and Ni²⁺ on aerobic granular sludge, improvement strategies such as pretreatment, desorption and adjustment of process parameters were proposed. By adopting improved strategies, aerobic granular sludge can still effectively treat printing and dyeing wastewater under adverse conditions. The research results provide suggestions for further exploration and application of aerobic granular sludge.

[Abstract](233) [FullText HTML] (175) [PDF 777KB](135)

Research on Dynamic Simulation of Eight Degrees of Freedom Automobile Model

QUE Xiaoyu, TIAN Guoying, FANG Tao, WEN Ke, YE Hao

2020, 34(4): 337-345.

Abstract:
The vehicle vibration system is a very complex system. In order to accurately reflect the vibration of the whole vehicle, based on certain assumptions, the eight degrees of freedom vibration model for a car was established by using Newton method in Matlab software. Based on the analysis of vehicle dynamic response characteristics in time domain, a four-wheel correlation road model was established based on filtered white noise and the second-order Pade algorithm. The accuracy of the road surface was verified, and it was used as the excitation input to the vehicle vibration model. The Newmark explicit integration method was used to solve the problem. The time-domain signal of each response was transformed into the frequency-domain response signal, and compared with the frequency-domain simulation of the vibration system. The results show that the model has good reliability and fast solution speed. Furthermore, the influences of the position of body mass center, suspension stiffness, tire stiffness and suspension damping on the comfort of driver and body centroid were further studied. Based on the original vehicle parameters, suggestions for improving vehicle comfort were put forward.

[Abstract](255) [FullText HTML] (287) [PDF 1607KB](84)

Design of Train Passenger Flow Monitoring System Based on BSSID Technology

QIAN Xiaogang, HU Guo, LI Hao

2020, 34(4): 346-350.

Abstract:
In order to monitor the flow density of high-traffic area and realize the flow diversion from dense area to scattered area, a train passenger flow monitoring system based on basic service set identifier (BSSID) technology was developed. The system was composed of Java minicomputer, BSSID address detection program and background manager program. Taking advantage of Java minicomputer, the numbers of passengers around can be detected through the BSSID detection program, and using Redis cache and other technologies, the performance of the system can be improved. After uploading the data to the server, data integration and visualization were conducted on the server side. The practical result shows that this system can realize the monitoring and channeling of train passenger flow under the epidemic and normal conditions, which can provide a new possibility for the construction of modern intelligent subway and promote the development of subway informatization.

[Abstract](210) [FullText HTML] (142) [PDF 718KB](118)

Simulation and Optimization Method of Transfer Streamline in Metro Transfer Station Based on VISSIM

GENG Yaning, HU Hua, WANG Tao

2020, 34(4): 351-357.

Abstract:
The design of transfer line in metro transfer station is the key to affect the efficiency and service level of passenger transfer. The optimization design principle and typical optimization design strategy of metro transfer station were given. Based on VISSIM simulation software, the simulation modeling process and method of metro transfer line were proposed, and the parameter calibration and correction method of pedestrian expected speed were deeply studied. Combined with the design objective and the function of simulation software, the evaluation index system of transfer line optimization of metro transfer station was established. Finally, a metro transfer station was taken as an example for example analysis, the results show that the proposed simulation modeling, parameter calibration and evaluation method have practical application value, which can provide reference for the design, improvement and evaluation of the transfer line of metro transfer stations in big cities in China.

[Abstract](226) [FullText HTML] (231) [PDF 940KB](95)

Evaluation of Rolling Bearing Performance Degradation Based on PCA-SVDD

WU Yilan, LIAO Aihua, DING Yaqi

2020, 34(4): 358-363.

Abstract:
Aiming at the problem that it is difficult to detect the early weak faults of rolling bearing in time, a rolling bearing performance degradation evaluation model based on principal component analysis (PCA) and support vector data description (SVDD) was proposed. PCA method was used to weighted fusion of the characteristic indexes of rolling bearing vibration signal in time domain and frequency domain, and a comprehensive characteristic index which can effectively and comprehensively describe the operation status of rolling bearing was constructed. The comprehensive characteristic indexes of normal samples were input into the SVDD model to complete the construction of evaluation model. The occurrence time of minor fault was determined by setting health alarm threshold, and the whole life test data of the rolling bearing was used for verification. The results show that compared with the SVDD model that the kurtosis index and the root mean square value as the characteristic index input, the evaluation model can detect the occurrence of early weak faults of rolling bearing earlier, and can describe the overall degradation of rolling bearing more accurately.

[Abstract](205) [FullText HTML] (132) [PDF 1175KB](65)

Economic Analysis of Combined Solar Hot Water System in Shanghai Based on TRNSYS

DENG tingting, CAI yingling, LIU kai

2020, 34(4): 364-368, 396.

Abstract:
Aiming at the singleness of current economic evaluation method of solar hot water system, the cost unit price of hot water was introduced to analyze the economic efficiency of solar thermal system. Taking a typical family of three in Shanghai as an example, the outlet temperature of solar collector in Shanghai area was simulated and analyzed based on TRNSYS software, and the hot water unit price of solar hot water system with different forms of auxiliary energy was calculated. The results show that the hot water unit price of electric assisted solar water heating system is 146.75 yuan per ton, which is 40.2% less than that of gas assisted solar water heating system.

[Abstract](222) [FullText HTML] (144) [PDF 1316KB](57)

Research on Grass Recognition of Mowing System Based on Machine Vision

AI Yongping, TANG Qiaoxing, WANG Zejie, MO Qinglin

2020, 34(4): 369-374.

Abstract:
In order to realize the grass recognition in the mower system, plan the moving path of the mower and cut the grass automatically, the target detection algorithm of single shot multibox detector (SSD) and convolutional architecture for fast feature embedding (Caffe) were used to train the grass recognition model on the mower. Pictures of grass cutting field were taken by raspberry pie (RPi) and sent to the working machine. The coordinate values of the grass in the picture were calculated by the working machine and returned to raspberry pie, and the axle rotation angle, the running time and direction of the rear wheel motor according to the coordinate value of the grass were calculated automatically, and then the mechanical parts of the mower were mobilized to mow the grass. The experimental results show that compared with the traditional manual mechanical mower or fence mower, the trained grass recognition model can recognize the grass normally, and the mower can better plan the mowing path automatically, which has a certain weeding effect. The research results realize the combination of machine vision and traditional machinery, and provide some ideas for the future research of intelligent machinery.

[Abstract](247) [FullText HTML] (158) [PDF 973KB](98)

Solutions to Deviation in Closure Site of Long-Span Cable-Stayed Bridge

WANG Shijie

2020, 34(4): 375-379.

Abstract:
Taking a cable-stayed bridge in Boffa Province, Guinea as an example, the shortness of the link section encountered during the closure process on the construction site was analyzed. Based on the unstressed state method, the finite element software was used for simulation calculation, and combined with the actual measured data on site, the closure plan was contrapuntally drawn up. The calculated and measured results show that selecting the non-low temperature period for direct linking with the existing section has little effect on the closured state of the cable-stayed bridge. This solution ensures that the bridge can be safely closured, and which provides a certain reference for the treatment of similar problems encountered in construction process of other large-span cable-stayed bridges.

[Abstract](215) [FullText HTML] (149) [PDF 890KB](86)

Mechanism Research on Influence of Clothing Product Sense of Superiority on Consumers’ Purchase Behavior

WANG Jingjin, WANG Hongyan, HU Shouzhong

2020, 34(4): 380-386.

Abstract:
The sense of superiority is an important psychological standard that affects consumers′ purchasing behavior of clothing products. The influential factors of clothing product sense of superiority were extracted using grounded theory research method. Based on the literature research, the influential factor model of clothing product sense of superiority on consumers’ purchasing behavior was established, and the survey data were empirically analyzed with SPSS26.0. Through verification, it is concluded that the influencing factors of sense of superiority have significant positive influence on consumers’ purchase intention and payment intention. The research results provide a theoretical basis for exploring the key factors and internal operation mechanism of sense of superiority on consumers, and provide countermeasures and suggestions for the development of new clothing products

[Abstract](578) [FullText HTML] (194) [PDF 847KB](175)

Research on Evaluation of Residents’ Health Level Based on Cloud Model

WU Yiqi, XIAO Xiang, LI Boyan, YIN Yu, GU Xi

2020, 34(4): 387-391.

Abstract:
Combined with the formation mechanism of ‘mismatching’ chronic non-infectious diseases and based on the traditional fuzzy comprehensive evaluation, a evaluation model of residents’ health level based on cloud model was established from four dimensions of ecological environment, life style, medical security and work pressure. The cloud model would fully excavate the information in the data, and quantify the fuzziness and randomness of the evaluation indexes, which makes the government’s decision evaluation and control strategy more scientific and targeted.

[Abstract](182) [FullText HTML] (180) [PDF 813KB](48)

A New Method of Power Sum for Natural Numbers

QIAO Shenyuan, LIANG Yikong

2020, 34(4): 392-396.

Abstract:
A function integral and form extension of the power sum of natural numbers was studied. By using Taylor expansion and the extended mean value theorem of integrals, the series expansion of the integral form of any real number power was given. Some examples were given to verify the effectiveness of the expansion.

[Abstract](289) [FullText HTML] (559) [PDF 653KB](129)

2020 Vol. 34, No. 4