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104 results on '"Mao, Shimin"'

2. Research on Calculation and Optimization Methods for Tooth Flash Temperature and Meshing Power Loss of the Gear System in Drum Shearer.

Author

Bai, Bo, Mao, Run, Guo, Wenchao, and Mao, Shimin

Subjects
TEETH, MECHANICAL models, TEMPERATURE distribution, SURFACE temperature, MECHANICAL wear, ADHESIVE wear
Abstract

The operating conditions of the drum shearer are very complex, and its ranging arm gear system often suffers from gear scuffing and wear. Gear scuffing is caused by the adhesive wear, which is due to the instantaneous friction and flash temperature of the tooth surface, and the gear meshing power loss is also caused by tooth surface friction. In order to resist tooth scuffing and improve meshing efficiency of the transmission system, an improved semi-analytical tooth surface flash temperature calculation method was used. The tooth flash temperature status under various working conditions were analyzed in detail. Based on the mechanical model of the shearer drum picks, the load condition of the drum was analyzed. Under these load and boundary conditions, the misalignments of each gear pair in the ranging arm were calculated. The tooth surface load distribution was calculated under the gear misalignments, and then the theoretical tooth surface flash temperature and meshing power loss were determined. Next, the tooth micro-geometry was modified to reduce flash temperature and meshing power loss. The flash temperature distribution pattern of the optimized tooth surface was studied under various working conditions, and the meshing power loss was also obtained. Finally, experiments were conducted to verify the effects of the optimized tooth surface on the friction temperature rise and the effectiveness of the modification method. Tooth surface optimization aimed at reducing tooth surface flash temperature can also effectively reduce meshing power loss, which has a significant effect on gear anti-scuffing and energy saving. [ABSTRACT FROM AUTHOR]

Published
2024
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4. Large-deformation and high-strength amorphous porous carbon nanospheres

Author

Yang, Weizhu, Mao, Shimin, Yang, Jia, Shang, Tao, Song, Hongguang, Mabon, James, Swiech, Wacek, Vance, John R, Yue, Zhufeng, Dillon, Shen J, Xu, Hangxun, and Xu, Baoxing

Subjects
Engineering, Macromolecular and Materials Chemistry, Materials Engineering, Chemical Sciences
Abstract

Carbon is one of the most important materials extensively used in industry and our daily life. Crystalline carbon materials such as carbon nanotubes and graphene possess ultrahigh strength and toughness. In contrast, amorphous carbon is known to be very brittle and can sustain little compressive deformation. Inspired by biological shells and honeycomb-like cellular structures in nature, we introduce a class of hybrid structural designs and demonstrate that amorphous porous carbon nanospheres with a thin outer shell can simultaneously achieve high strength and sustain large deformation. The amorphous carbon nanospheres were synthesized via a low-cost, scalable and structure-controllable ultrasonic spray pyrolysis approach using energetic carbon precursors. In situ compression experiments on individual nanospheres show that the amorphous carbon nanospheres with an optimized structure can sustain beyond 50% compressive strain. Both experiments and finite element analyses reveal that the buckling deformation of the outer spherical shell dominates the improvement of strength while the collapse of inner nanoscale pores driven by twisting, rotation, buckling and bending of pore walls contributes to the large deformation.

Published
2016

5. Analysis of the Influence of Eccentricity Error of Gear Skiving Cutting Tool Movement on Gear Skiving Accuracy

Author

Guo Wenchao, Yang Yu, Mao Shimin, and Guo Zheng

Subjects
Skiving, Mechanical engineering and machinery, TJ1-1570
Abstract

The skiving cutting tool movement eccentricity error has obvious influences on skiving gear accuracy. Based on the theoretical and experimental study of skiving，the influences of cutting tool eccentricity error on the helix deviations and the tooth profile deviations of the workpiece machined by skiving and action mechanism are investigated. Firstly，experiments of skiving process method are carried out，which are focused on the skiving waves on the tooth flanks of the workpieces，it is found that the amplitude of the waves can be decreased by reducing the tool eccentricity error. Then，based on the experiment study，the theoretical analysis of the influences of tool eccentricity error on the helix deviations and the tooth profile deviations of the workpiece are carried out，and the wave generation mechanisms and periodic characteristic are investigated. Finally，based on the experiments and theoretical study，the design method of number of tooth of skiving cutting tool，which can be used to improve the gear skiving waves on the tooth surface of the workpieces is proposed.

Published
2020
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21. Kinematic Analysis of Rotary Transplanting Mechanism for Wide-Narrow Row Pot Seedlings

Author

Xiaoqiang Du, Zhao Yun, Mao Shimin, Zhang Guofeng, Liu Xiaolong, and Sun Liang

Subjects
0209 industrial biotechnology, Engineering, business.product_category, business.industry, Frame (networking), Biomedical Engineering, Soil Science, Forestry, 02 engineering and technology, Kinematics, Mechanism (engineering), Gear train, 020303 mechanical engineering & transports, 020901 industrial engineering & automation, Transformation matrix, 0203 mechanical engineering, Control theory, Trajectory, Bevel gear, Transplanting, business, Agronomy and Crop Science, Simulation, Food Science
Abstract

Wide-narrow row pot seedling transplanting (WPST) could obtain high rice yield and quality. In this study, a new type of mechanism for WPST is designed based on analysis of recent advances at home and abroad. The WPST mechanism, which consists of planetary gear trains with seven noncircular bevel gears, is used in an automatic rice pot seedling transplanter. The working trajectory and attitude properties are analyzed according to the agronomy requirements of rice WPST. To establish the kinematics, a non-uniform B-spline curve is used to fit and control the outer pitch curve of the noncircular bevel gears, and D-H transformation matrices are introduced to express the trajectory and attitude of the planting paw in the world frame of the WPST mechanism. Computer-aided analysis and an optimization program of the WPST mechanism are developed. Based on the program, the effects of various parameters on transplanting trajectory and attitude are analyzed. By human-machine interaction, the structural parameters that meet the demands of the WPST mechanism are optimized. Using these parameters, a 3D model of the mechanism is built, and virtual simulation and physical prototype tests are carried out. The simulation and experimental results agree with the theoretical analysis, which validates the theoretical model of the WPST mechanism.

Published
2016

25. Stretchable Electronics: In-Plane Deformation Mechanics for Highly Stretchable Electronics (Adv. Mater. 8/2017)

Author

Su, Yewang, primary, Ping, Xuecheng, additional, Yu, Ki Jun, additional, Lee, Jung Woo, additional, Fan, Jonathan A., additional, Wang, Bo, additional, Li, Ming, additional, Li, Rui, additional, Harburg, Daniel V., additional, Huang, YongAn, additional, Yu, Cunjiang, additional, Mao, Shimin, additional, Shim, Jaehoun, additional, Yang, Qinglin, additional, Lee, Pei-Yin, additional, Armonas, Agne, additional, Choi, Ki-Joong, additional, Yang, Yichen, additional, Paik, Ungyu, additional, Chang, Tammy, additional, Dawidczyk, Thomas J., additional, Huang, Yonggang, additional, Wang, Shuodao, additional, and Rogers, John A., additional

Published
2017
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27. In‐Plane Deformation Mechanics for Highly Stretchable Electronics

Author

Su, Yewang, primary, Ping, Xuecheng, additional, Yu, Ki Jun, additional, Lee, Jung Woo, additional, Fan, Jonathan A., additional, Wang, Bo, additional, Li, Ming, additional, Li, Rui, additional, Harburg, Daniel V., additional, Huang, YongAn, additional, Yu, Cunjiang, additional, Mao, Shimin, additional, Shim, Jaehoun, additional, Yang, Qinglin, additional, Lee, Pei‐Yin, additional, Armonas, Agne, additional, Choi, Ki‐Joong, additional, Yang, Yichen, additional, Paik, Ungyu, additional, Chang, Tammy, additional, Dawidczyk, Thomas J., additional, Huang, Yonggang, additional, Wang, Shuodao, additional, and Rogers, John A., additional

Published
2016
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29. Epidermal radio frequency electronics for wireless power transfer

Author

Huang, Xian, primary, Liu, Yuhao, additional, Kong, Gil Woo, additional, Seo, Jung Hun, additional, Ma, Yinji, additional, Jang, Kyung-In, additional, Fan, Jonathan A., additional, Mao, Shimin, additional, Chen, Qiwen, additional, Li, Daizhen, additional, Liu, Hank, additional, Wang, Chuxuan, additional, Patnaik, Dwipayan, additional, Tian, Limei, additional, Salvatore, Giovanni A., additional, Feng, Xue, additional, Ma, Zhenqiang, additional, Huang, Yonggang, additional, and Rogers, John A., additional

Published
2016
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34. Chiral Separation of Racemic Mandelic Acid by the Coupling Crystallization Process and Simulated Moving Bed Technology

Author

Mao, Shimin

Subjects
simulated moving bed, nucleation and growth kinetics, metastable zone, mobile phase composition, parameter estimate, racemic compound solubility, Mandelic acid, frontal analysis, FBRM, inverse method, Process Control and Systems, cooling crystallization, ATR-FTIR, competitive adsorption isotherms
Abstract

Chirality is a major concern in the modern pharmaceutical, food and agricultural industries. The importance of enantiopure drugs has risen dramatically in recent years due to FDA regulations requiring that all chiral bioactive molecules must be isolated and tested for the efficacy and safety, and have to be as pure as possible containing a single pure enantiomer. There are essentially three strategies that can be applied to obtain single pure isomers: (a) extraction from plants and animal materials (b) enantio-selective asymmetric synthesis so that only one isomer is formed in the first place, or (c) making a racemate and finding a method for separating the enantiomers. Only few enantiomers exist in nature and most of them are racemates. A highly efficient chiral asymmetric synthesis route would be the ideal situation, but it usually takes about 10-15 years to develop a synthesis recipe. Hence, the best strategy would be to synthesize the drug in racemate form and separate the isomers to produce single pure enantiomer. Among the variety of enantioseparation methods, chromatography and crystallization are the most dominant methods for the recovery of pure enantiomers. However, both methods have limitations. Crystallization cannot obtain enantiopure enantiomers from the racemic compound directly. In SMB, solvent consumption increases exponentially if desired purity requirement is close to 100%. In this work, the coupling of SMB for enrichment followed by direct crystallization is applied for the chiral resolution to circumvent limitations of each method. In order to take advantage of both the processes, SMB chromatography is used for partial enrichment thereby reducing solvent consumption followed by direct crystallization to obtain 100% pure enantiomers. Here, the chiral resolution of mandelic acid as racemic compound was considered to investigate the performance of the hybrid SMB-crystallization process theoretically as well as experimentally. The solubility and metastable zone limit of (R,S)-MA and (R)-MA in water and the crystallization kinetics parameters of (R,S)-mandelic acid and (R)-mandelic acid by optimization of the crystallization model based on the necessary experimental data collected in unseeded cooling batch crystallizers were determined. For the SMB part, the choice of mobile phase and determination of binary competitive equilibrium isotherms parameters of (R,S)-Mandelic acid and the experimental and modeling studies of SMB process have also been accomplished.

Published
2012

46. Dissolvable Metals for Transient Electronics

Author

Yin, Lan, primary, Cheng, Huanyu, additional, Mao, Shimin, additional, Haasch, Richard, additional, Liu, Yuhao, additional, Xie, Xu, additional, Hwang, Suk‐Won, additional, Jain, Harshvardhan, additional, Kang, Seung‐Kyun, additional, Su, Yewang, additional, Li, Rui, additional, Huang, Yonggang, additional, and Rogers, John A., additional

Published
2013
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