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1. Integrated interpretation of pXRF data on ancient nephrite artifacts excavated from Tomb No.1 in Yuehe Town, Henan Province, China

Author

Dian Chen, Yimin Yang, Baotong Qiao, Jingpu Li, and Wugan Luo

Subjects
Jade, Nephrite, pXRF, Non-destructive analysis, Statistical analysis, Fine Arts, Analytical chemistry, QD71-142
Abstract

Abstract Previous studies of ancient jade using portable X-ray fluorescence (pXRF) have mostly focused on mineral identification, alteration status and provenance determination. It is usually used as an auxiliary instrument for spectroscopic detection with finer resolution. However, there is no substitute for the efficiency and stability of pXRF in-situ non-destructive analysis, which is less affected by the test environment. The scale of the data from the pXRF analysis did not allow for a more in-depth interpretation of ancient jade in the past. In this study, pXRF has been carried out for a total of 112 pieces of nephrite artifacts unearthed from the Yuehe tomb No.1 in Nanyang City, Henan Province, Central China. Certain patterns become clearer as the size of the data increases. The coefficient of variation, cluster analysis and correlation analysis can be used to separate elements into different assemblages, revealing whether the elements are from the primary and impurity minerals of nephrite itself, from the burial microenvironment in the soil, or even from other specific sources. In addition, most of the secondary whitening occurring in the batch of nephrite are accompanied by an increase in Ca content, confirming the previously refuted theory of calcification. More importantly, the principal component analysis of the twin nephrite artifacts suggests visually indistinguishable elemental changes caused by secondary changes, which may lead to misjudgment of ancient nephrite provenance using elemental data.

Published
2022
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2. On-Load Electromagnetic Compatibility Test and Simulation Closed-Loop of the Electric Drive System of New Energy Vehicles

Author

Xinwen Luo, Weize Liu, and Jingpu Li

Subjects
Article Subject, Modeling and Simulation, Energy Engineering and Power Technology, Electrical and Electronic Engineering
Abstract

In order to solve the problem of high-amplitude and high-frequency interference generated by the electric drive system of new energy vehicles, the author proposes a closed-loop research method for on-load electromagnetic compatibility testing and simulation for electric drive systems of new energy vehicles. The method includes EMC design of the electric drive system on-load test equipment, establishment of a conducted EMI simulation platform for the electric drive system under load conditions, and optimization of the conducted EMI performance of the electric drive system based on key parameters and PWM control. Experimental results show that if the parasitic inductance of the IGBT gate increases, the conducted emission level in the frequency range of 2∼30 MHz will increase, and there is basically no change at the low frequency, and the position of each resonance point shifts to the relatively low frequency. The experiment was replaced with the DPWM3 modulation mode, and the conducted emission amplitude was reduced by about 2 dBμV in the range of 200 kHz∼2 MHz, and there was basically no change on the whole. Conclusion. It is proved that the electromagnetic compatibility closed-loop development technology of the electric drive system of new energy vehicles under load conditions can meet the development needs of new energy vehicles in the environment where energy problems and air pollution problems are becoming more and more serious.

Published
2022
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3. Comparison of the Posterior-anterior Approach and Lateral-medial Approach for Complex AO/OTA Type C Intra-articular Fractures of Distal Humerus

Author

Haibo Xu, Yongchang Chen, Zhongsheng Wei, Gang Wang, Xiao Wang, Guoqing Zheng, Jian Chen, Jingpu Li, Fei Xiao, Lin Wei, and Jialei Tu

Subjects
Text mining, business.industry, Medial approach, Distal humerus, Medicine, Intra-articular fracture, Anatomy, business, Posterior anterior
Abstract

Objective: The aim of this retrospective study was to investigate clinical effects of the treatment of intra-articular distal humeral fractures via the combined posterior olecranon osteotomy and anterior approach and the combined lateral Kaplan approach associated with the medial approach. Methods: Between July 2010 and September 2019, 28 cases of intercondylar fractures of the distal humerus (AO/OTA type C) were treated by open reduction and internal fixation (ORIF) via the posterior and anterior approach and combined lateral-medial approach, which were divided into the P-A (n = 13) and L-M (n = 15) groups, respectively. The outcomes in terms of function were assessed using the range of motion (ROM) of the elbow and forearm, humerotrochlear (HT) angle, Visual Analogue Scale (VAS) scores, Mayo Elbow Performance Score (MEPS), and efficacy grade evaluated using the scoring system of Orthopaedic Trauma Association (OTA) at the one-year follow-up. Results: The flexion-extension of elbows and pronation-supination of forearms were respectively 114.1° ± 12.4° and 157.3° ± 9.6° in the P-A group and 117.1° ± 14.5° and 161.3° ± 10.7° in the L-M group. No significant difference was observed between the two groups for the elbow and forearm ROM (p > 0.05). Furthermore, surgery duration, blood loss volume, HT angle, MEPS, VAS scores, OTA rating, and the morbidity of postoperative complications during the one-year follow-up did not differ between groups. Conclusion: The posterior olecranon osteotomy and anterior approach can be used efficiently for exposure of complex distal humeral injuries with similar clinical efficacy and complications in the treatment of intra-articular distal humeral fractures as compared to the lateral-medial approach.

Published
2021

6. Optimization of Clutchless AMT Shift Control Strategy for Electric Vehicles.

Author

Jingpu Li, Pengcheng Sheng, and Kaikai Shao

Subjects
*ELECTRIC vehicles, *POWER transmission, *ELECTRIC power transmission, *HYBRID electric vehicles, *BRUSHLESS electric motors
Abstract

With the development of the economy, the number of cars in China is rapidly expanding, which has caused a certain degree of pollution to the environment. The emergence of electric vehicles has the good evasive effect on this issue. In order to shorten the shifting time of the electric clutchless automatic mechanical transmission (AMT) and reduce the shifting shock, the DC brushless drive motor, the clutchless and synchronizer-free AMT and the final drive are combined to establish the electric vehicle power transmission model of the drive motor and AMT controlled by the power transmission integrated controller. And the dynamic analysis of the picking phase, the shift process, and the torque reduction and torque recovery phases are carried out. Based on the dynamics of the shifting process, the implementation flow of the coordinated control of the shifting process is created. The classical PD control algorithm is used to optimize its control strategy and realize the optimal shift control of the clutchless AMT of electric vehicles. The experimental results show that the electric vehicle with the shift control strategy has a shifting time of 720 ms-750 ms in the static, low speed, medium speed and high speed state, and the impact degree is inside ±10 m·s-3 during the shifting process. This shows that the electric vehicle using the proposed shift control strategy has less time for shifting, high shifting quality, and smooth shifting process. [ABSTRACT FROM AUTHOR]

Published
2020

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