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Adaptive Time-varying Sliding Surface for Second-Order Variable Structure Control
Zhiping Zhu,Kui Yuan,Huosheng Hu 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
This paper introduces an adaptive time-varying sliding surface for the second order variable structure controlsystem which can improve the robustness of the control system by shortening the reaching phase. A saturation functionis adopted to replace the conventional sign function in the controller to decrease the switching frequency of the sliding control action and thus to reduce the chattering of the system.
( Zhiping Peng ),( Bo Xu ),( Antonio Marcel Gates ),( Delong Cui ),( Weiwei Lin ) 한국인터넷정보학회 2015 KSII Transactions on Internet and Information Syst Vol.9 No.7
In the dynamic cloud computing environment, to ensure, under the terms of service-level agreements, the maximum efficiency of resource utilization, it is necessary to investigate the online dynamic management of virtual machine resources and their operational application systems/components. In this study, the feasibility and properties of the division of virtual machine resources on the cloud platform, using the virtual machine cluster as the management unit, are investigated. First, the definitions of virtual machine clusters are compared, and our own definitions are presented. Then, the feasibility of division using the virtual machine cluster as the management unit is described, and the isomorphism and reconfigurability of the clusters are proven. Lastly, from the perspectives of clustering and cluster segmentation, the dynamics of virtual machines are described and experimentally compared. This study aims to provide novel methods and approaches to the optimization management of virtual machine resources and the optimization configuration of the parameters of virtual machine resources and their application systems/components in large-scale cloud computing environments.
Zhiping LIU,Wei YU,Xuan WU 한국곤충학회 2019 Entomological Research Vol.49 No.8
Most species of Staphylinidae are predators in an agroecosystem. They acquire prey information from their environment through receptors. In this study, the sensilla on maxillary and labial palps of Philonthus kailiensis, Philonthus lewisius and Quedius robustus were examined with scanning electron microscopy to identify and analyse the external morphology and distribution of the sensilla to enhance our knowledge of the sensilla of Staphylinidae and provide a rationale of taxonomical studies on the two genus. Results showed that the sensilla are classified into six types: Böhm bristles, sensilla chaetica, sensilla furcate, sensilla coeloconica, sensilla placodea and sensilla basiconica. No sexual dimorphism exists among the three species. The relationships and functions of sensilla on maxillary and labial palps were also speculated. There may be a certain correlation between the sensilla on maxillary and labial palps of the staphylinid and its habitat.
Compressive Mechanical Properties and Shock-Induced Reaction Behavior of a Ti–29Nb–13Ta–4.6Zr Alloy
Zhiping Guo,Ran Liu,Chuan Ting Wang,Yong He,Yuan He,Yue Ma,Xuebing Hu 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.10
The compressive mechanical properties of a Ti–29Nb–13Ta–4.6Zr alloy were investigated at room temperature under variousstrain rates. The parameters of a modified Johnson–Cook constitutive equation were determined to describe the strainsoftening behavior under dynamic conditions. The testing results under compression show yield strength evidently increaseswith the increase of the strain rate. Moreover, it was found that the strain-rate effect of the yield strength upon dynamicdeformation is more significant than that upon quasi-static deformation. In order to characterize the impact-initiated reactionbehavior of Ti–29Nb–13Ta–4.6Zr alloy, the quasi-sealed test chamber was used to measure the pressure caused by energyreleased of fragments. It was obviously shown that the exothermic chemical reaction was more intense with the increase ofimpact velocity.
Zhiping Wang,Jianghuai Hu,Ke Zeng,Gang Yang 한국고분자학회 2017 폴리머 Vol.41 No.5
An adenine-containing curing agent, 9,10-bis(4-aminophenyl) adenine (p-APA) was designed to decrease the volatility of curing agent. The exact structure of p-APA was confirmed by proton nuclear magnetic resonance (1H NMR), infrared spectroscopy (IR) and elementary analyzer (EA). Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were measured to compare volatility of p-APA with that of a traditional curing agent, 1,3-bis(4-aminophenoxy) benzene (4-APB), which indicated p-APA has better thermal stability and lower volatility. The thermal tests of different curing process of phthalonitriles showed good thermal and thermo-oxidative stabilities. The thermal property was improved along with increasing curing temperature and time and the glass-transition temperature (Tg) was not observed on DSC before 400℃. The Fourier transform infrared spectroscopy (FTIR) showed that triazine and phthalocyazine rings were the dominant reaction products of the cured phthalonitriles. The dynamic mechanical analysis (DMA) of post-cured phthalonitriles showed a storage modulus of 1.3 GPa at 40℃ and Tg about 500℃.
Zhiping Zhai,Donghai Yuan,Yuezheng Lan,Haixu Zhao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.10
During the operation of a forage crusher, the common issues usually faced are shorter mean time between failures and low reliability. The hammer rotor, a critical component, is prone to fatigue fracture, hammer wear, violent vibration of the rotor system caused by uneven wear of the hammers, and other issues that reduce the machine's service life and reliability. In order to avoid failure modes within the design life of the forage crusher and improve its reliability, the functional functions of the fatigue fracture failure, hammer wear failure, and resonance failure modes were established, the marginal distribution functions for each individual failure mode were computed, and the reliability model of the hammer rotor under multiple failure modes is constructed based on the correlation degree between the failure modes. On this basis, the reliability of the forage crusher is improved by optimizing the structure and working parameters. Before optimization, the fatigue reliability, wear reliability, and vibration reliability of the hammer rotor are 0.878, 0.94, and 0.248, respectively, and the reliability of the hammer rotor under multiple failure modes is 0.2116. After optimization, the fatigue, wear, and vibration reliability are 0.979, 0.9997, and 0.932, respectively. The reliability of the hammer rotor under multiple failure modes is 0.923, which reduces the probability of failure within the design life and meets the requirement that the reliability of key parts of agricultural and animal husbandry machinery is not less than 90 %. This study validates the reliability models and multi-objective optimization results and serves as a reference for forage crusher structural reliability design and optimization.
A Sliding Mode Control Design based on the Reaching Law for Matrix Rectifiers
Zhiping Wang,Yunshou Mao,Zhanhu Hu,Yunxiang Xie 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.3
This paper presents a novel approach for achieving both a tight DC voltage regulation and a power factor control by applying the Reaching Law Sliding Mode Control (RL-SMC) and the conventional Sliding Mode Control (SMC). Applying these strategies on a matrix rectifier (MR) can achieve a unity grid side power factor when the DC load changes widely and it can provide a ripple-free output voltage that is easily affected by distortions of the three-phase ac voltage supply. Furthermore, by employing the reaching law on the SMC can solve the chatting problem of the sliding motion. Comparative Matlab simulations and experimental verifications for these strategies have been presented and discussed in this paper. The results show that by applying the SMC and RL-SMC on a MR can achieve a unity grid side power factor and a regulated ripple-free DC output.
Zhiping Lei,Yazhou Li,Zhao Lei,Xue Yang,Jingchong Yan,Zhanku Li,Hengfu Shui,Shibiao Ren,Zhicai Wang,Ying Kong,Shigang Kang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.117 No.-
Large-scale preparation of cheap and high-performance carbonaceous materials is in urgent need due tothe huge demand of carbonaceous materials-organic binder composites for Joule heating. Here, carbonbasedelectrothermal composites with high electrical conductivity were fabricated by adjusting the morphologyand structure of pitch-based carbonaceous materials (PC) through the use of graphene asstructure-directing agent to tune the orientation and carbonization of coal pitch. It is demonstrated thatthe addition of graphene can effectively promote the formation of graphitized carbon, increase the contentof sp2C, reduce defective carbon and increase the graphite interlayer spacing. 1% graphene-added PCPVDFcomposite exhibits 290% increase in the carrier concentration, 190% enhancement in mobility, and67% reduction in the volume resistivity compared to PC-PVDF composite. Molecular simulations elucidatethat the graphene edges favor pitch carbonization and improve the orientation factor and energy gap ofcarbon materials. This study provides clues for design of low-cost pitch-derived carbon materials-bindercomposites.
Zhiping Lei,Hengfu Shui,Lian Wu,Lijuan Gao,Muxin Liu,Zhicai Wang,Shibiao Ren 한국공업화학회 2013 Journal of Industrial and Engineering Chemistry Vol.19 No.5
NaOH depolymerized products (SDP) of Shengli lignite was used as lignite-based heavy carbon resources in this study. Hydrotreatment of SDP over Ni–Mo/Al2O3 and Ni–Mo/Zr–Al2O3 catalysts was investigated. It was found that the incorporation of Zr to Ni–Mo/Al2O3 catalyst results in the easy reduction of metal oxides and the increase of the stacking degree and length of MoS2 slabs. Both of Ni–Mo/Al2O3 and Ni–Mo/Zr–Al2O3 catalysts show better performance for hydrogenation of SDP and can be used repeatedly. The incorporation of Zr to Ni–Mo/Al2O3 catalyst significantly inhibits the formation of tetrahydrofuran insolubles (THFI), promotes the formation of two-ring aromatics and increases HS yield compared to that over Ni–Mo/Al2O3 catalyst.