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2021, 41(11): .

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2021, 41(11): .

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An Overview on Unmanned Vehicle Technology in Off-Road Environment

HU Yuhui, WANG Xu, HU Jiaming, GONG Jianwei, WANG Ke, LI Guipeng, MEI Cheng

2021, 41(11): 1137-1144. doi:10.15918/j.tbit1001-0645.2020.144

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Abstract:
Unmanned driving technology(UDT) in off-road environment is one of the important research areas in the field of intelligence in recent years.UDT in off-road environments plays an important role in promoting the development of military intelligence and improving the efficiency of industrial and agricultural production,possessing military strategic significance and civil economy value.In this paper,the research status of UDT in off-road environment was summarized from three aspects: perception and navigation positioning,path planning and motion control.The key technologies of UDT in off-road environment and the problems in the application of these technologies were described.In addition,the future research direction and focus of UDT in off-road environment were prospected.

Experimental Study on Impact Resistance of Glass Fiber Reinforced Plastic/Rigid Polyurethane Foam Sandwich Structures Under Air Blast Loading

ZENG Xiang, LIU Yan, XU Zejian, HUANG Fenglei

2021, 41(11): 1145-1153. doi:10.15918/j.tbit1001-0645.2021.036

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Abstract:
Air blast tests were conducted to investigate the dynamic response and blast resistance of polyurea coated glass fiber reinforced plastic (GFRP) sandwich structure, GFRP sandwich structures with single rigid polyurethane foam core layer and with two rigid polyurethane foam core layers. All sandwich structures have the same areal-density. The failure modes of three kinds of panels were founded and the impact resistance of three structures was compared. The results show that the failure modes of the panel includes shear fracture at fixed boundary, bending crack at the corner and shear crack at the place with stress concentration. Crushing zone, crack coalescence zone, debonding with panels and tensile crack are observed in the core layers. The damage degree and residual deformation of GFRP sandwich structures with two rigid polyurethane foam core layers and polyurea coated GFRP sandwich structure with polyurea on front surface are larger than those of GFRP sandwich structure with single rigid polyurethane foam core layer. The damage degree of polyurea coated GFRP sandwich structure with polyurea on back surface is larger than that of GFRP sandwich structure with single rigid polyurethane foam core layer, however, the residual deformation of the back panel is significantly reduced.

Study on Structure Strength of Bushing in Swinging Pair of Connecting Rod Based on Optimization of Process Parameters

XIANG Jianhua, LIU Jian, ZHONG Chenglong, WEI Manhui, WANG Yujiang, ZHANG Limin

2021, 41(11): 1154-1161. doi:10.15918/j.tbit1001-0645.2020.150

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Abstract:
In this paper, the residual stress produced in bushing under strong spinning was simulated by finite element method, and the structure strength characteristics of the swinging pair of connecting rod with residual stress were analyzed based on temperature equivalent simulation method. Furthermore, the law analysis and optimization calculation of bushing process parameters such as thinning rate, feed ratio and heat treatment temperature were carried out according to the stiffness and strength characteristics of the bushing in swinging pair of connecting rod. The results show that the thinning rate, spindle speed and feed ratio have little effect on the value of residual stress. The residual stress is distributed symmetrically along the axial direction and is larger at both ends. In the swinging pair working of connecting rod, the residual stress can make the maximum stress and maximum deformation increase, and where the residual stress is larger, the larger of the increase. But the residual stress has a little effect on the contact pressure. Using the response model, the optimal process parameters got based on the stress and deformation of this type of bushing are the thinning rate 28.37%, the feed ratio 0.154 and the heat treatment temperature 261.73 ℃.

Influence of Aggregate Size on Mechanical Properties of Concrete

WANG Jiangbo, ZHANG Tianxing, DING Junsheng, GAO Guangfa, ZHENG Teng

2021, 41(11): 1162-1170. doi:10.15918/j.tbit1001-0645.2020.118

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Abstract:
In order to study the influence of coarse aggregate size on the mechanical properties of concrete,the quasi-static compression and splitting tensile experiments of M40,M80 and M110 mortars and concrete with different coarse aggregate sizes were conducted by MTS. The quasi-static compressive stress-strain curve and splitting stress-time curve of each specimen were obtained. Then,the influence of coarse aggregate size on different grade concrete was analyzed. Moreover,the influence of mortar compressive strength and aggregate size on concrete compressive strength was studied by means of two-way analysis of variance. The results show that the compressive strength,Young's modulus and tensile strength of concrete have a similar change tendency with the coarse aggregate size increased,in other words,the tendency of first increasing and then decreasing. The effect of coarse aggregate size on the concrete compressive strength is increased with mortar strength increasing,but the influence on Young's modules is decreased with the mortar strength increased. The influence of mortar compressive strength on concrete compressive strength is greater than that of aggregate size.

Novel Cascade Control Based on Damp Variable Sliding Mode Control for Electro-Hydrostatic Actuator

FU Yongling, LI Yupeng, WANG Mingkang, LIN Ziwang, ZHU Deming

2021, 41(11): 1171-1178. doi:10.15918/j.tbit1001-0645.2021.044

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Abstract:
An electro-hydrostatic actuator (EHA) is a typical mechanical/hydraulic system suffering from high level of nonlinearity and parametric uncertainties. In this paper, based on sliding mode control (SMC), a novel control scheme, adaptive damping variable sliding mode control (ADV-SMC) was proposed to handle the preceding uncertainties. The method overcame the influence of friction and external disturbance by the robustness of sliding mode control. And variable damping method was used to suppress the overshoot of step response. The parameter adaptation law was driven by tracking errors. The task of the robust item was alleviated due to the presence of parameter adaptation. Consequently, the tracking performance was further improved. Besides the theoretical proof of an asymptotic tracking performance, numerical experiments were also conducted to verify the effectiveness of the proposed method.

Bearing Fault Warning Based on MFPH and Improved VMD

MA Xiaoping, LI Bohua, CAI Manli, HAN Zhenghua, CHEN Zepeng

2021, 41(11): 1179-1187. doi:10.15918/j.tbit1001-0645.2020.128

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Abstract:
To solve the problem of bad real-time performance of traditional bearing fault early warning and the accuracy affection of fault feature extraction on the early warning effect, transferring the idea of speech endpoint recognition, a double threshold method was used based on the MFPH feature to track the fault starting point. Firstly, in order to overcome the influence of parameter selection and endpoint effect of variational mode decomposition (VMD)on the feature extraction, based on the grid search method of energy difference, the parameters were optimized, and the breakpoint effect was suppressed by SVR. Then, combined with the advantages of MWPE in detecting the randomness of vibration signals, the ability of VMD to reconstruct the signals was fully utilized and the fault signal after the starting point was extracted. Finally, the effectiveness of this method in bearing fault warning was demonstrated by the experiment of bearing fault signal.

Adaptive Weighted Clustering Algorithm for Large-Scale Satellite Cluster Network

CHEN Yu, ZHANG Yong, CHEN Shi

2021, 41(11): 1188-1192. doi:10.15918/j.tbit1001-0645.2021.072

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Abstract:
To overcome the shortcomings of the plane management structure in the large-scale satellites cluster network, an adaptive distributed weighted clustering algorithm (ADWCA) was proposed. It was arranged to calculate the comprehensive weight of each satellite node in the initialization phase on the ground and to divide the nodes into cluster head and member node according to the predictability of the satellites network operation. And then, labeled cluster head and member node, the satellites were maintained in a completely distributed manner based on their neighbors and their own information. Simulation analysis results show that, compared with the lowest-Id algorithm and the highest-connectivity degree algorithm, the cluster structure generated by this algorithm possesses fewer clusters, better stability, and can effectively balance the load of cluster head nodes.

Weighted Adaptive Guided Filtering Based on Kurtosis Variance

FANG Hongping, ZENG Ruoyun, WU Jiaxin, WU Shiqian

2021, 41(11): 1193-1200. doi:10.15918/j.tbit1001-0645.2020.239

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Abstract:
To overcome the difficulty in extracting edge of noise image with traditional local window variance, a kurtosis coefficient variance was introduced to percept edges of noise image. Meanwhile, a novel weighted adaptive guiding filter (WAGIF) was proposed. Firstly, the fixed regularization parameter of traditional guiding filter was adjusted adaptively based on edge information of local window. Secondly, the weighted aggregation was achieved based on the multi-neighbor window edge weight. And then edge blurring was further suppressed. Experimental results show that the average PSNR and SSIM on different noise levels are boosted above 65% and 78% respectively using WAGIF. Filtering results show better performance in noise smoothing and edge-preserving according to state-of-the-art image filters.

A Wrapper Method for Combining Subset Feature with Cascade Pre-learning

PAN Limin, TONG Tong, LUO Senlin, QIN Xiaonan

2021, 41(11): 1201-1206. doi:10.15918/j.tbit1001-0645.2019.117

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Abstract:
Feature selection algorithms in the machine learning domain can simplify the input of model, improve interpretability, and avoid dimensional catastrophe and over-fitting. In terms of selecting features on wrapper methods, the evaluation of models usually take the feature subsets filtered by the search algorithm as input directly, which leads to the fact that feature exploitation and evaluation of models is restricted by the feature reconstruction and fitting ability of the evaluation model. Moreover, the more appropriate feature subsets were limited to be discovered either. To solve the problems, a pre-learning wrapper method was proposed based on the cascade forest structure. Adding multi-level cascade forest between the search algorithm and the evaluation model, the model was arranged to transform the feature subset as high-level feature set, reducing the difficulty of recognition in the evaluation and improving the performance of feature subset. In contrast experiment, a variety of search algorithms and evaluation model combinations were evaluated on multiple datasets. The results indicate that the proposed method can reduce the number of selected features, while maintaining classification performance and the low coupling property of wrapper methods.

HAN Yi, DU Yanhui, CHEN Qinggang, LU Tianliang

2021, 41(11): 1207-1214. doi:10.15918/j.tbit1001-0645.2021.056

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To solve the problem of difficulty in obtaining personal privacy information of Internet users, incomplete and uncommon or even false content of the public information, a trajectory similarity analysis method was proposed based on time sliding window model. Firstly, some location data with universal, objective and reflecting capability for user behavioral habits were selected as similarity analysis base to collect the data of Sina Weibo and Didi Taxi, forming two high-value data sets with the characteristics of domestic netizens as experimental objects. And then, a trajectory similarity matching algorithm was developed based on the time sliding window. Adjusting the time window and theFvalue of the location distance optimization algorithm, it was arranged to realize the similarity analysis of users of different network platforms. Finally, some validation experiments were carried out based on the user location data of Sina Weibo and Didi Taxi. The results show that geographical location is a positive correlation factor for virtual identity similarity judgment, and the similarity average F-value can reach up to 90%.

Real-Time Accurate Pupil Detection Based on a Master-Slave Camera System

WANG Xiangzhou, ZHU Lulu, ZHENG Shuhua, NAN Ruoyu

2021, 41(11): 1215-1221. doi:10.15918/j.tbit1001-0645.2020.155

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Abstract:
Aiming at real-time and accurate pupil detection, a master-slave camera tracking eye image capture system was proposed to capture eye images. The master camera was arranged to locate the face, and the slave camera was arranged to track the eye area in real time under the cloud platform and to collect high-resolution eye images. In order to improve the dynamic performance of the system, a fusion algorithm of AdaBoost face detection and MOSSE target tracking was adopted for the face image with the resolution of 1280×960 from the master camera, realizing a fast face location of 60 fps. A semantic segmentation network was used to locate the pupil diameter of the eye image from the camera to obtain the region of interest of the pupil. The pupil of the interest region was detected accurately with an ellipse fitting algorithm. The experimental results show that the proposed detection system and method can achieve 18 fps pupil detection. The effective pixel of pupil image can reach more than 2 500, and the detection repeatability can reach ±1.06%.

Research on the Influence of Laser and Microwave Power on ESR Spectrum of the Diamond Nitrogen Vacancy Centre Ensemble Magnetometer

GAO Yang, XU Chaoqun, HUANG Kui, GAO Yuting, LIU Chaobo, WU Nankai, LIU Mingjun, ZHANG Chao, XIAO Qi, YI Zhong

2021, 41(11): 1222-1225. doi:10.15918/j.tbit1001-0645.2021.187

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Abstract:
Both laser power and microwave power have an important influence on the sensitivity of the diamond nitrogen-vacancy (NV) center ensemble magnetometer based on continuous-wave optically detected magnetic resonance (CW-ODMR) measurement pulse. A set of confocal magnetic field detection system was built based on the ensemble of the diamond NV center. By adjusting the laser power and microwave power, the full width at half maximum (FWHM) and contrast of the corresponding electron spin-resonance (ESR) spectrum could be measured. Experiments indicated that the FWHM of the spectrum was mainly affected by the microwave power, and the spectral contrast was affected by both microwave power and laser power. An obvious light narrowing of the FWHM was observed when the microwave power was constant and the laser power was increased. The optimal parameters of the system can be obtained in two steps. First, adjust the microwave power to get an applicable FWHM of the spectrum. Then increase the laser power to obtain a satisfactory contrast and FWHM of the spectrum.

Synthesis and Application of Stimulus-Responsive Polyoxometalate-Viologen-Based Compounds

XU Yanqing, ZHEN Miaomiao

2021, 41(11): 1226-1235. doi:10.15918/j.tbit1001-0645.2021.047

Abstract(322) PDF(171)

Abstract:
Polyoxometalate-viologen-based compounds are constructed by viologen derivatives and polyoxometalates via coordination bond, electrostatic attraction of anions and cations and weak hydrogen bond. The polymetallic oxygen clusters are introduced to the structure functioning as electron donors for its electron-rich inorganic nature, providing electrons to viologen cation. This strategy sublimates the application of organic-inorganic hybrid materials and serves an effective method. This kind of material features diverse structure designs, favorable photothermal stability and multi-stimulus responses. This review summarizes the synthesis, structure and properties, and the electron transfer pathway in stimulus response materials of polyoxometalate-viologen analogue crystalline compounds, together with their applications in the field of smart sensing and photocatalysis in recent years. At last, this review summarizes the challenges and shortcomings in this field and prospects for future research.

Research on Selecting of P-gp Aptamers and Its Application

LI Yujuan, LIANG Min, WU Guangxia, SUN Xinxin, LIU Shan, DENG Yulin

2021, 41(11): 1236-1244. doi:10.15918/j.tbit1001-0645.2020.192

Abstract(328) PDF(156)

Abstract:
The SELEX technology was used to select aptamers (Apt) of permeability glycoprotein (P-gp). The enzyme linked immunosorbent assay (ELISA) and surface plasmon resonance (SPR) methods were used to determine the affinity between Apts and P-gp. Apt5 was chosen to evaluate the inhibitory effect on P-gp efflux function with immortalized human brain capillary endothelial cells (hCMEC/D3) and human epithelial colorectal adenocarcinoma cells (Caco-2). As a result, ten of 81bp Apts were selected. The affinity order of Apt was Apt5>Apt8>Apt1>Apt4>Apt6>Apt10>Apt7>Apt2>Apt9>Apt3. Further research showed that Apt5 significantly increased the cellular accumulation of rhodamine 123 both in hCMEC/D3 and Caco-2 cells, with a fold of 40.77% (P<0.01) and 32.39% (P<0.05), respectively, which indicated that Apt5potentially inhibited the efflux function of P-gp. In present study, several Apt of P-gp are presented, which had high affinity with P-gp and could inhibit P-gp efflux function. These Apts might be potential novel P-gp inhibitor.

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2021 Vol. 41, No. 11

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