bob手机在线登陆学报自然版

2022, 42(2): .

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2022, 42(2): .

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Virtual Research on Durability of Large Special Freight Vehicle

RONG Jili, LI Xianhang, WANG Xi, HU Changhua

2022, 42(2): 111-117. doi:10.15918/j.tbit1001-0645.2021.086

Abstract(275) PDF(98)

Abstract:
Durability is a research hotspot in the field of vehicles. The physical fatigue test on vehicles is costly and time-consuming. In order to shorten the development cycle and reduce research costs, a virtual test method was proposed to study the durability of vehicles. Firstly, a finite element model was established for a research object of a large special freight vehicle, and the results of stress distribution and frame deformation were obtained through static analysis; the modal information of the flexible body structure was obtained through modal analysis. And then, based on the modal stress recovery theory, considering the flexible body of the frame, upper swing arm, lower swing arm and force axis, a rigid-flexible coupling model of the whole vehicle was established, and the dynamic response of driving on a flat road was obtained. Compared with experiment results, the root mean square value of the vertical acceleration at the measuring point of the frame is in acceptable range, validating the correctness of the model. Finally, according to the Palmgren-Miner criterion, the driving life of the vehicle was evaluated on grade D roads. The results show that the fatigue life of the 4 axle suspension structure is the smallest, and the lower swing arm structure has obvious stress concentration. An improved lower swing arm structure can increase its service life, providing a reference for the design of vehicle structure.

Deformation Mechanism of Floating Model Subjected to Underwater Explosion Load

SUN Yuanxiang, CHEN Yanwu, WANG Cheng, WANG Yongqiang

2022, 42(2): 118-127. doi:10.15918/j.tbit1001-0645.2021.116

Abstract(314) PDF(98)

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In order to reveal the deformation mechanism of the ship's bottom plate subjected to the underwater explosion load, a floating body model was designed, the experimental research and theoretical analysis were carried out. Considering the spherical waves effect of the close-in explosion, the shock waves energy was obtained. The wall pressure time history measured by PVDF was used as the input load of the floating model, and the change of buoyancy on the model was considered, then the maximum kinetic energy of the model was obtained. The coupling effect of the membrane tensile strain and the bending strain is considered, the plastic deformation energy of the bottom plate was obtained by using the fitted bottom plate deflection function. The sum of kinetic energy and plastic deformation energy of the model divided by the sum of shock wave energy and bubble energy, so the energy utilization rate is obtained. The energy utilization rate increases first and then decreases with the increase of the dimensionless numberΦ. When theΦis 50～90, the floating body model has the highest utilization rate of underwater explosion energy, reaching 20%～30%.

Evaluation of Mechanical Properties of TC4 Titanium Alloy Drill Pipe in Corrosive Environment

AN Chen, CHENG Zhi, HUANG Xu, SHA Aixue, LI Rong, QIU Ming, DUAN Menglan

2022, 42(2): 128-134. doi:10.15918/j.tbit1001-0645.2020.214

Abstract(458) PDF(74)

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In order to study the adaptability of titanium alloy drill pipe materials to corrosive environments, according to corrosion requirements and test standards in NACE and GB, several processes were carried out. Firstly, some TC4 titanium alloy specimens were corroded and a comparison group without corrosion treatment was set. And then a series of tensile, impact and hardness tests were carried out to study its comprehensive mechanical properties under corrosive conditions. The results show that under the corrosion conditions of NaCl, H₂S, CO₂and 205 ℃, the tensile properties of TC4 titanium alloy decrease by no more than 10%, the impact performance changes by only 0.33%，and the hardness decreases by 3.21%, indicating that TC4 titanium alloy possesses high corrosive resistance, can maintain better comprehensive mechanical properties under corrosive conditions. Taking the requirements of steel drill pipe materials in the API as an index, the mechanical properties of TC4 after corrosion treatment are shown as follows, yield strength, tensile strength and elongation are not lower than that of X grade steel, impact absorption energy is 62% higher than that of API requirement (20 ℃), the hardness exceeds that of G grade steel by about 37%, close to that of S grade steel. Therefore, TC4 titanium alloy can be used in corrosive well drill pipes to avoid or reduce the corrosion failure of the drill pipes.

Control Strategy of the Range-Extender for Electric Vehicles with V2G

WEI Hongqian, ZHANG Youtong, JIANG Xinzhu, AI Qiang, ZHAO Wenqiang

2022, 42(2): 135-144. doi:10.15918/j.tbit1001-0645.2021.239

Abstract(323) PDF(84)

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Range-extender (RE) benefits to enlarge the driving mileage of electric vehicles; however, knowledge gap lies in the research of the V2G function of RE. To this end, this paper investigates the grid-connected generation and control strategies of RE. Firstly, a novel electrical position estimation algorithm was proposed based on the decoupling double synchronous reference frame phase-locked loop approach, and the Hall feedforward signal was incorporated to improve its response speed and estimation accuracy. On this basis, the grid phase-locked loop and voltage control were coordinated. Then, the multi-objective optimization was executed to optimize control variables to reduce the fuel consumption and unnecessary mechanical start-off. Besides, the start-off scheme and condition switch strategy were investigated in depth. Finally, a RE experimental platform with the engine, motor and generation devices was established to validate the electrical angle estimation algorithm, grid-connected generation strategy and condition regulation scheme. Results validate the executability and effectiveness of the proposed RE control strategy with V2G function.

Prediction of In-Vehicle VOC Concentrations Based on Small-Scale Chamber Test

WANG Haimei, TONG Liping, XIONG Jianyin

2022, 42(2): 145-151. doi:10.15918/j.tbit1001-0645.2021.129

Abstract(253) PDF(103)

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Volatile organic compounds (VOC) emitted from vehicle interior decorations seriously affect the in-cabin air quality. The emission characteristics of VOC from vehicle materials are mainly characterized by three key emission parameters: the initial emittable concentrationC₀, the diffusion coefficientD_mand the partition coefficientK. In this paper, a ventilated-chamber C-history method was used to determine three key parameters of six target VOC emitted from several typical vehicle interior decorations, and investigate the influence of temperature on them. To predict the concentration of VOC emitted from multi-source materials coexisted in the vehicle cabin, a multi-source model was established, and to simulate the real vehicle environment, a 3 m³experimental system was established for verification experiments. The good agreement between the simulations and experiments demonstrates that the key emission parameters determined via small-scale chamber tests can be used to assess emission scenarios for real vehicle cabin environments.

Research on Urban Spatial Evolution Based on Multi-Source Data—A Case Study of the Beijing-Tianjin-Hebei

WANG Yufeng

2022, 42(2): 152-157. doi:10.15918/j.tbit1001-0645.2020.219

Abstract(216) PDF(58)

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In order to solve the shortcomings of traditional research methods in the detection of urban spatial evolution, a new method was proposed to respond to China's land refinement transformation, and to improve the in-depth application of optical satellite and remote sensing technology in the social and economic fields. Based on the Beijing-Tianjin-Hebei urban agglomeration, urban evolution and industrial transfer models were used to analyze the spatial and temporal characteristics of its evolution from 1990 to 2020. The results show that, ① the overall evolution intensity presents an "up-down" trend, showing the hot spots of evolution around Beijing, Tianjin and Tangshan, and Shijiazhuang-Baoding cities. ②The comprehensive development of Beijing, Tianjin and Tangshan cities shows a downward trend, while that of Shijiazhuang, Handan and Xingtai cities shows an upward trend. ③The regional industrial chain shows a trend of agglomeration and diffusion in space. The middle and high technical industries gather in the larger cities, while the middle and low technical industries move to the surrounding cities. The research proves that optical satellite possesses great potential in urban development monitoring, which can provide a certain reference for the planning and decision-making of regional integrated development.

Stigmergy-Based Swarm Robots for Target Search and Trapping

FAN Zhun, SUN Fuzan, MA Peili, LI Wenji, SHI Ze, WANG Zhaojun, ZHU Guijie, LI Ke, XIN Bin

2022, 42(2): 158-167. doi:10.15918/j.tbit1001-0645.2020.217

Abstract(367) PDF(108)

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As a classical but difficult problem, multi-target searching and entrapping in a swarm of robots have received more and more attention in recent years. However, most existing approaches for addressing this problem rely on unrealistic assumptions such as reliable communication links, available global coordinate system, known environmental information, and central coordination among robots. Therefore, in this paper, a stigmergy mechanism-based framework was proposed for the use of searching and entrapping targets in a swarm of robots. Improving the inverse ant colony system, the framework was designed by adding a variety of pheromones to help group robots to collaborate and explore the environment and generate pheromone maps. Meanwhile, combining the Hierarchical Gene Regulatory Network (H-GRN) model with pheromone maps generated in the previous stage, the framework was arranged for robotic systems to search and entrap dynamic targets in unknown and communication-limited environments. Simulation results show that, comparing with traditional methods, the proposed framework can achieve better performance in target searching and trapping.

Research on the Inspiring Effects of Design Thinking with Functional Terms

NIU Hongwei, HAO Jia, WANG Lu, ZHOU Yongjia

2022, 42(2): 168-176. doi:10.15918/j.tbit1001-0645.2020.203

Abstract(196) PDF(54)

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To study the inspiring effects of functional terms as external stimuli information, on the basis of analyzing the information processing of design thinking with functional term stimulation, some function terms were taken as external stimuli to carry out a design experiment. Based on the empirical results from an experiment involved 40 student designers, two research findings were generated. The first is that functional terms can make the quantity of generated design schemes decreased, but the usefulness of the generated design schemes significantly increased. The second is that, compared with high level functional terms, the low level functional terms can decrease the quantity, novelty and variety of generated design schemes, but can increase usefulness of generated design schemes. This may imply that middle level functional terms can produce better balanced design ideas, which can be used as the best external stimuli for designer.

Low-Rank Matrix Approximation Based Method for DOA Estimation under Nonuniform Noise Background

WEN Chao, XU Liyun, DUAN Pengting

2022, 42(2): 177-183. doi:10.15918/j.tbit1001-0645.2020.232

Abstract(260) PDF(82)

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To solve the performance degrade problem of DOA estimation with few snapshots under nonuniform noise in the traditional discretization free methods, a discretization free parameter estimation method was proposed based on atomic norm minimization and annihilation filter. Firstly, the continuity of parameter space was exploited to construct a sparse representation model of array signal based on atom gathering situation, converting the signal covariance matrix recovery into the atomic norm minimization problem. Then, making full use of the Hermit Toeplitz structure and low-rank characteristics of the signal covariance matrix, the atomic norm minimization problem was transformed into a low-rank matrix approximation based practically solvable semi-definite programming problem. Thereby, the signal covariance matrix was restored.
Finally, the annihilating filter coefficients were solved based on the annihilating filter theory to carry out DOA parameter estimation. Simulation results show that the proposed method can provide higher estimation accuracy and more robustness than existing similar methods under the condition of non-uniform noise and few snapshots. The root mean sguare error of this method was reduced by 59.4% on average compared with existing methods, under different maximum noise power ratio conditions.

Parameter Disturbance Suppression Method of PMSM

ZHANG Shuo, LI Xuerong, CUI Xing, WANG Yang, ZHANG Chengning

2022, 42(2): 184-191. doi:10.15918/j.tbit1001-0645.2021.215

Abstract(275) PDF(99)

Abstract:
In permanent magnet synchronous motor（PMSM）control system，there are motor parameter disturbances. In order to improve the performance of deadbeat predictive current control (DPCC), the motor parameter disturbances are need to be compensated. In this paper, firstly a mathematical model of PMSM was used to analyze the influence of parameter disturbance on DPCC. And then, an autoregression model was designed for the estimation of stator resistance disturbance and stator inductance disturbance, using the disturbances of the previous several control periods to estimate the parameter disturbance of current control period. Finally, the estimated parameter disturbances were compensated to the input of DPCC to control the PMSM. Simulation and experimental results show that the proposed method can effectively suppress the disturbance of PMSM stator resistance and stator inductance.

Improved SIFT Feature Extraction and Matching Based on Spectral Image Space

DING Guoshen, QIAO Yanli, YI Weining, DU Lili

2022, 42(2): 192-199. doi:10.15918/j.tbit1001-0645.2020.024

Abstract(243) PDF(59)

Abstract:
As a method to measure the spatial properties of image, the Gaussian kernel with different parameters was used to get the difference in original SIFT algorithm, while the difference in the spectral dimension of optical system was used in the proposed method. Comparing with traditional sift method and a lot of improved methods, counting the image block pixel information only in the neighborhood around the feature points, the new method was arranged to divide the matching process into two steps. Firstly, the image block pixel information got from the neighborhood of the feature points was rough matched. And then four matching pairs with the highest similarity were selected as the benchmark matching pairs, and the feature points were checked twice. The simulation results show that the proposed method can significantly increase the number of detected feature points and effectively eliminate the error matching.

3D Target Recognition Algorithm Based on Point-Pair Features of Key Points

LU Jun, WEI Panyi, WANG Wei

2022, 42(2): 200-207. doi:10.15918/j.tbit1001-0645.2020.078

Abstract(235) PDF(111)

Abstract:
In order to improve the speed and accuracy of 3D point cloud target recognition in complex scenes, a 3D target recognition algorithm based on the features of the pairs of key points was proposed. Firstly, point-pair features were established for key points to avoid the feature calculation of local surfaces in the surrounding neighborhood, to reduce space dimensionality and to improve calculation speed. Then a hash table was taken as storage to reduce the time of feature matching, a fast voting scheme was utilized to match and identify the model point cloud and the scene point cloud for the generation of candidate position and pose, and a greedy algorithm was used to cluster and filter the positions and poses. And an ICP algorithm was adopted to optimize the object positions and poses, according to the overlapping rate of registered point clouds to evaluate the point cloud recognition. Finally, some experiments were carried out based on data sets and real scenarios to validate the proposed algorithm. The results show that the proposed recognition method can present better feasibility, effectiveness and robustness to noise, possessing certain practical engineering application value.

A Robust Digital Watermarking of NSCT-Zernike under Compressed Sensing

ZHANG Tianqi, YE Shaopeng, ZHOU Lin

2022, 42(2): 208-214. doi:10.15918/j.tbit1001-0645.2020.226

Abstract(241) PDF(59)

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To meet the high requirements of watermarking robustness against geometric attacks, a robust digital watermarking scheme was proposed based on the combination of non-subsampled Contourlet transform under compressed sensing and pseudo Zernike moments. First, the original image was decomposed to extract its low-frequency components by non-subsampled Contourlet transform, and the low-frequency components were sparsed by discrete wavelet transform to obtain sparse bases. And then, the measurement matrix was constructed, compressed sensing processing was performed, the Zernike moments were calculated, and the watermark information was embedded by quantizing the amplitude of the regularized pseudo Zernike moment. Finally, a regularized orthogonal matching pursuit algorithm was used to reconstruct the image compressed sensing. Simulation and experimental results show that when the peak signal to noise ratio reaches more than 40 dB, the proposed algorithm can ideally extract the NC value and bit error rate of the watermark.

Study on Chemical Constituents inFerula feruloides

JIN Pengfei, LI Min, LI Shaoyong, YIN Hongquan, TANG Shengan

2022, 42(2): 215-222. doi:10.15918/j.tbit1001-0645.2021.241

Abstract(217) PDF(51)

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To study the chemical constituents ofFerula. ferulaeoides(Steud.) Korov. and their antitumor activities, it's chemical constituents were separated and purified by sephadex LH-20, silica gel, semi-preparative high performance liquid chromatography (HPLC) methods, and their structures were identified by physicochemical property and NMR, HRMS spectroscopic methods. The absolute configuration of new compound was determined by ECD. The cytotoxic activity of isolated compounds on human breast cancer (MCF-7) cell line was determined by MTT assay. Fifteen compounds (1-15) were isolated, and were identified as 1- (2- hydroxyl- 4- methoxybenzoyl)- 2S*- hydroxy- 5,9,13- trimethyl- 4(E),8(E),12- tetradecatrien- 1- one (1), guaiol (2), 1- (2,4- dihydroxyphenyl)- 3,7,11- trimethyl- 3- vinyl- 6(E),10- dodecadiene- 1- one (3)，dshamirone (4), 2,3- dihydro-7- hydroxy- 2S^*,3R^*- dimethyl- 2- [4,8-dimethyl- 3(E),7- nonadienyl]- furo[3,2-c]coumarin (5),3- (2-hydroxyl-4-methoxybenzoyl)- 4S^*,5R^*- dimethyl- 5- [4,8- dimethyl- 3(E),7(E)- nonadien- 1- yl]tetrahydro- 2- furanone (6)，fukanedone A (7), 2,3- dihydro- 7- methoxy- 2S^*,3R^*- dimethyl- 2- [4- methyl- 5- (4-methyl-2-furyl)- 3(E)- pentenyl]- furo[3,2-c]coumarin (8), umbelliprenin (9), 2,3- dihydro- 7- methoxy- 2S^*,3S^*- dimethyl- 3- [4,8- dimethyl- 3(E),7- nonadienyl]- furo[3,2-c]coumarin (10), 2,3- dihydro- 7- methoxy- 2S^*,3R^*- dimethyl- 3- [4,8-dimethyl-3(E),7-nonadienyl]- furo[3,2-c]coumarin (11), 2,3- dihydro- 7- hydroxy- 2S^*,3R^*- dimethyl- 3- [4,8- dimethyl- 3(E),7- nonadienyl]- furo[3,2-c]coumarin (12), 2,3- dihydro- 7- methoxy- 2S^*,3R^*- dimethyl- 2- [4,8- dimethyl- 3(E),7- nonadienyl]- furo[3,2-c]coumarin (13),2,3- dihydro- 7- methoxy- 2R^*,3R^*- dimethyl- 2- [4,8- dimethyl- 3(E),7- nonadienyl]- furo[3,2-c]coumarin (14), ferulaeone C (15). Compound1is a new compound, compound9is isolated from this plant for the first time. Compounds3、4、5and15show potential antitumor activity with 50% inhibitory concentration ( IC₅₀) values of 15.11, 12.98, 18.01 and 12.87 μmol/L, respectively.

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