Multi-objective optimization of a co-rotating twin-screw gear transmission system based on heuristic search

Mingzhu Hu,Haixia Wang,Peitang Wei,Genshen Liu,Lei Zhang,Zhiqiang He,Hua iju Liu 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.11

The positive characteristics observed in terms of compact structural sizes and high torque-transmitting capacities have allowed co-rotating twin-screw (CRTS) gear transmissions to be extensively applied to instances requiring small central distances and large power densities. In this study, a multi-objective optimization model for the quick determination of structural parameters of the CRTS gear transmission system is proposed based on the heuristic search and non-dominant sorting genetic algorithm. Results reveal that the optimized scheme with 17 design variables and 18 constrained parameters can be achieved with this model. The system reduces mass by 7.74 % from the original mass of 199.06 kg, while the safety factor variance of the transmission system decreases by 29.3 %. This method applies to other transmission systems with different structures and thus provides general theoretical support for modern gear transmission optimizations.

Research on Artificial Fish Swarm Algorithm with Cultural Evolution for Subcarrier Allocation

LIU Mingzhu,LI Xin,ZHANG Mingyu,LI Chang 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.6

In the resource allocation process of multi-user OFDM system, in order to realize the purpose of maximizing the total transmission rate under constant power, a new subcarrier allocation algorithm has been proposed in this paper, which is to introduce cultural evolution method into the original artificial fish swarm algorithm. Because the population space in cultural algorithm framework has the advantage of guiding search process, the new algorithm can effectively overcome the defect of falling into local extreme which generally exists in the fish swarm algorithm in the resource allocation. At the same time, the proposed new algorithm also can make it easy to quantify the optimized goals and variable values. Simulation results show that the proposed artificial fish swarm algorithm with cultural evolution (CE-AFS) has been greatly improved the global search ability and convergence speed compared with the AFS algorithm and Shen algorithm.

Polyamide composite nanofiltration membrane modified by nanoporous TiO2 interlayer for enhanced water permeability

Mingzhu Chi,Pingyun Zheng,Mingxin Wei,Aimei Zhu,Lubin Zhong,Qiugen Zhang,Qinglin Liu 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.115 No.-

The traditional polyamide composite nanofiltration membrane has high selectivity. However, low waterpermeability is an important problem to be solved. Herein, the conventional polyamide compositenanofiltration (TFC) membrane was modified with nanoporous TiO2 (nTiO2) interlayer throughvacuum-assisted strategy for enhanced water permeability. By tuning the nTiO2 nanoparticles loading,the nTiO2 modified TFC membrane with crumpled structure was fabricated. Besides, the thickness ofpolyamide layer was reduced due to the hydrophilicity and porosity of nTiO2. Because of the larger effectivefiltration area and thinner polyamide layer, the modified membrane had a permeability of12.8 L m2 h1 bar1 (increased by 20.8% than that of TFC membrane) and a rejection of 98.2% when filteringNa2SO4 aqueous solution. This work provided a solution for enhanced water permeability andextended the application of TiO2 in the modification of polyamide composite nanofiltration membrane.

Shaking Table Test Study on Dynamic Response of Bedding Rock Slope with Weak Rock

Mingzhu Guo,Chen Wang,He Zhang,Kunsheng Gu,Huang Liu 대한토목학회 2022 KSCE Journal of Civil Engineering Vol.26 No.8

A shaking table model test was conducted to study the dynamic response and failure mechanism of a bedding rock slope with weak rock layer based on the “Xiaguiwa” landslide in the Jinsha River basin of Sichuan-Tibet. The influence of schist-like weak rock layer on bedding rock slope is considered. The test results show that the Peak Ground Acceleration (PGA) amplification coefficient varies rhythmically from the inside to the surface of the slope, and 0.3 gand 0.6 g are the slope appears cracking and instability. schist-like weak rock layer makes the seismic wave enhance obviously, but in the slope flexure position, the seismic wave near the weak rock layer is slightly weakened instead, and the maximum displacement often occurs above the weak rock layer. the “bucking” occurs at 1/4 of the slope height, and the fracture degree at the middle and lower part of the slope is greater than that at the middle and upper part, and the slope damage surface appears to be “concave at the top and convex at the bottom”. The damage process of the model slope is divided into four stages. The model test results reflect the influence of the weak rock layer on the seismic dynamic response and damage process of the bedding rock slope.

HOPF BIFURCATION IN NUMERICAL APPROXIMATION FOR DELAY DIFFERENTIAL EQUATIONS

Zhang, Chunrui,Liu, Mingzhu,Zheng, Baodong 한국전산응용수학회 2004 Journal of applied mathematics & informatics Vol.14 No.1

In this paper we investigate the qualitative behaviour of numerical approximation to a class delay differential equation. We consider the numerical solution of the delay differential equations undergoing a Hopf bifurcation. We prove the numerical approximation of delay differential equation had a Hopf bifurcation point if the true solution does.

Hopf bifurcation in numerical approximation for delay differential equations

Chunrui Zhang,Mingzhu Liu,Baodong Zheng 한국전산응용수학회 2004 Journal of applied mathematics & informatics Vol.14 No.-

In this paper we investigate the qualitative behaviour of numerical approximation to a class delay differential equation. We consider the numerical solution of the delay differential equations undergoing a Hopf bifurcation. We prove the numerical approximation of delay differential equation had a Hopf bifurcation point if the true solution does.

Synthesis of CeO2 Porous Nanospheres with Tunable Pore and Particle Sizes and Their Adsorption to Methyl Orange

Longfeng Li,Chengyu Li,Mingzhu Liu,Cheng Wang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.11

The catalytic performance of ceria oxide (CeO2) was greatly influenced by the materials' structure and surface area. In this paper, CeO2 porous nanospheres (PNS) with tunable pore and sphere sizes were synthesized by a solvothermal method using diethylene glycol as reaction media. All the as-synthesized CeO2 PNS presented good adsorption capacity for methyl orange, which makes them potential application in waste water treatment conveniently and economically. The control over the sphere and pore sizes of CeO2 PNS was achieved by regulating the volume of water bubble in the reaction system, which supplied limited room for the assembling of preformed CeO2 small nano-precursors.

Structure and morphological characteristics of polygonal salt crust, the West Juyan Lake, China

Guoming Zhang,Yuting Xiao,Mingzhu Xiang,Chang Hong,Bo-Tao Zhang,Lianyou Liu,Peijun Shi,Jifu Liu 한국지질과학협의회 2022 Geosciences Journal Vol.26 No.3

Polygonal salt crust patches (PSCPs) in modern playas have critical hydrologic implications for arid areas, but the morphology and origin of these polygonal features are under debate. This study investigated the structure and morphological characteristics of crustal landforms in a modern playa located in the West Juyan Lake, western Inner Mongolia of China, through an integrated analysis of high-resolution remote sensing images obtained from Google Earth, pedestrian field surveys, and unmanned aerial vehicle photography. The study area covers approximately 2,650 ha and the number of salt crust patches was 3,491. Across this area, the coverage and number of salt crust patches varied with elevation and sedimentary environment. The results show that the polygonal patch pattern of the salt crust landforms was fractal, and similar polygonal patch perimeter to area ratios and landscape index values prevail in the study area. The wind erosion of material on the surface of the Gobi Desert, a mountain torrent alluvial fan, and material carried by seasonal river water probably provided the provenance of the regional salt crust landforms. The structure and morphological characteristics of salt crust in typical playas of the arid and semiarid region are important for better understanding their composition and sedimentary environment. This study can help reveal relevant information regarding environmental change and provide a reference for saline dust emissions from playas in arid areas.

Green Synthesis of Multifunctional Carbon Nanodots and Their Applications as a Smart Nanothermometer and Cr(VI) Ions Sensor

Lu Li,Congying Shao,Qian Wu,Yunjian Wang,Mingzhu Liu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.12

In this work, water-soluble and blue-emitting carbon nanodots (CDs) were synthesized from apple peels for the first time via one-step hydrothermal method. The synthetic route is facile, green, economical and viable. The as-prepared CDs were characterized thoroughly by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman, Fourier transform infrared (FT-IR), X-ray photoelectron (XPS), fluorescence and UV–Vis absorption spectroscopy in terms of their morphology, surface functional groups and optical properties. The results show that these CDs possessed ultrasmall size, good dispersivity, and high tolerance to pH, ionic strength and continuous UV irradiation. Significantly, the CDs had fast and reversible response towards temperature, and the accurate linear relationship between fluorescence intensity and temperature was used to design a novel nanothermometer in a broad temperature range from 5 to 65 ℃ facilely. In addition, the fluorescence intensity of CDs was observed to be quenched immediately by Cr(VI) ions based on the inner filter effect. A low-cost Cr(VI) ions sensor was proposed employing CDs as fluorescent probe, and it displayed a wide linear range from 0.5 to 200 μM with a detection limit of 0.73 μM. The practicability of the developed Cr(VI) sensor for real water sample assay was also validated with satisfactory recoveries.