Overview of the development of smart base isolation system featuring magnetorheological elastomer

Yancheng Li,Jianchun Li 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.24 No.1

Despite its success and wide application, base isolation system has been challenged for its passive nature, i.e., incapable of working with versatile external loadings. This is particularly exaggerated during near-source earthquakes and earthquakes with dominate low-frequency components. To address this issue, many efforts have been explored, including active base isolation system and hybrid base isolation system (with added controllable damping). Active base isolation system requires extra energy input which is not economical and the power supply may not be available during earthquakes. Although with tunable energy dissipation ability, hybrid base isolation systems are not able to alter its fundamental natural frequency to cope with varying external loadings. This paper reports an overview of new adventure with aim to develop adaptive base isolation system with controllable stiffness (thus adaptive natural frequency). With assistance of the feedback control system and the use of smart material technology, the proposed smart base isolation system is able to realize real-time decoupling of external loading and hence provides effective seismic protection against different types of earthquakes.

EXPERIMENTAL STUDY ON PID CONTROL OF MAGNETORHEOLOGICAL SHOCK ABSORBER UNDER IMPACT LOAD

Yancheng Li,Jiong Wang 한국소음진동공학회 2008 한국소음진동공학회 국제학술대회논문집 Vol.2008 No.7

Analysis and optimization of a typical quasi-zero stiffness vibration isolator

Huan Li,Yang Yu,Jianchun Li,Yancheng Li 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.27 No.3

To isolate vibration at a low-frequency range and at the same time to provide sufficient loading support to the isolated structure impose a challenge in vibration isolation. Quasi-zero stiffness (QZS) vibration isolator, as a potential solution to the challenge, has been widely investigated due to its unique property of high-static & low-dynamic stiffness. This paper provides an in-depth analysis and potential optimization of a typical QZS vibration isolator to illustrate the complexity and importance of design optimization. By carefully examining the governing fundamentals of the QZS vibration isolator, a simplified approximation of force and stiffness relationship is derived to enable the characteristic analysis of the QZS vibration isolator. The explicit formulae of the amplitude-frequency response (AFR) and transmissibility of the QZS vibration isolator are obtained by employing the Harmonic Balance Method. The transmissibility curves under force excitation with different values of nonlinear coefficient, damping ratio, and amplitude of excitation are further investigated. As the result, an optimization of the structural parameter has been demonstrated using a comprehensive objective function with considering multiple dynamic characteristic parameters simultaneously. Finally, the genetic algorithm (GA) is adopted to minimise the objective function to obtain the optimal stiffness ratios under different conditions. General recommendations are provided and discussed in the end.

Plasma Targeted Metabolomics Analysis for Amino Acids and Acylcarnitines in Patients with Prediabetes, Type 2 Diabetes Mellitus, and Diabetic Vascular Complications

Xin Li,Yancheng Li,Yuanhao Liang,Ruixue Hu,Wenli Xu,Yufeng Liu 대한당뇨병학회 2021 Diabetes and Metabolism Journal Vol.45 No.2

Background: We hypothesized that specific amino acids or acylcarnitines would have benefits for the differential diagnosis of diabetes. Thus, a targeted metabolomics for amino acids and acylcarnitines in patients with diabetes and its complications was carried out. Methods: A cohort of 54 normal individuals and 156 patients with type 2 diabetes mellitus and/or diabetic complications enrolled from the First Affiliated Hospital of Jinzhou Medical University was studied. The subjects were divided into five main groups: normal individuals, impaired fasting glucose, overt diabetes, diabetic microvascular complications, and diabetic peripheral vascular disease. The technique of tandem mass spectrometry was applied to obtain the plasma metabolite profiles. Metabolomics multivariate statistics were applied for the metabolic data analysis and the differential metabolites determination. Results: A total of 10 cross-comparisons within diabetes and its complications were designed to explore the differential metabolites. The results demonstrated that eight comparisons existed and yielded significant metabolic differences. A total number of 24 differential metabolites were determined from six selected comparisons, including up-regulated amino acids, down-regulated medium-chain and long-chain acylcarnitines. Altered differential metabolites provided six panels of biomarkers, which were helpful in distinguishing diabetic patients. Conclusion: Our results demonstrated that the biomarker panels consisted of specific amino acids and acylcarnitines which could reflect the metabolic variations among the different stages of diabetes and might be useful for the differential diagnosis of prediabetes, overt diabetes and diabetic complications.

Advances in Medical Needle Technologies – Geometry, Mechanics, Design and Manufacturing

Yancheng Wang,Weisi Li,Peidong Han,Marco Giovannini,Kornel Ehmann,Albert Shih 한국생산제조학회 2014 한국생산제조시스템학회 학술발표대회 논문집 Vol.2014 No.9(2)

Incidence of Online Public Opinion on Guangzhou Simultaneous Renting and Purchasing Policy - A data mining application

Yancheng Wang,Haixian Li 충남대학교 아시아여론연구소 2018 Asian journal for public opinion research Vol.5 No.4

This paper adopts the big data research method, and draws 491 data from the Tianya Forum about the Simultaneous Renting and Purchasing policy of Guangzhou. The qualitative analysis software Nvivo11 is used to cluster the main questions about the Simultaneous Renting and Purchasing policy in the forum. The 36 high-frequency word frequencies are obtained through text clustering. Through rooted theory analysis, the main driving factors for summarizing people's doubts are 9 main categories, 3 core categories, and the model of driving factors for online forums is established. The study finds that resource factors are the most key factor, economic factors are the important drivers, and policy guiding factors are sub-important drivers.

Incidence of Online Public Opinion on Guangzhou Simultaneous Renting and Purchasing Policy - A data mining application

Wang, Yancheng,Li, Haixian Center for Asian Public Opinion ResearchCollaborat 2018 Asian journal for public opinion research Vol.5 No.4

This paper adopts the big data research method, and draws 491 data from the Tianya Forum about the Simultaneous Renting and Purchasing policy of Guangzhou. The qualitative analysis software Nvivo11 is used to cluster the main questions about the Simultaneous Renting and Purchasing policy in the forum. The 36 high-frequency word frequencies are obtained through text clustering. Through rooted theory analysis, the main driving factors for summarizing people's doubts are 9 main categories, 3 core categories, and the model of driving factors for online forums is established. The study finds that resource factors are the most key factor, economic factors are the important drivers, and policy guiding factors are sub-important drivers.

Cometabolism degradation of lignin in sequencing batch biofilm reactors

Faguo Kuang,Yancheng Li,Lei He,Yongqiu Xia,Shubai Li,Jian Zhou 대한환경공학회 2018 Environmental Engineering Research Vol.23 No.3

Cometabolism technology was employed to degrade lignin wastewater in Sequencing Batch Biofilm Reactor. Cometabolic system (with glucose and lignin in inflow) and the control group (only lignin in inflow) were established to do a comparative study. In contrast with the control group, the average removal rates of lignin increased by 14.7% and total oarganic carbon increased by 32% in the cometabolic system with glucose as growth substrate, under the condition of 5 mg/L DO, 0.2 kgCOD/(m³·d) lignin and glucose 1.0 kgCOD/(mm³·d). Functional groups of lignin are degraded effectively in cometabolic system proved by fourier transform infrared spectroscopy and Gas Chromatography-Mass Spectrometer, and the degradation products were amides (mainly including acetamide, N-ethylacetamide and N, N-diethylacetamide), alcohols (mainly including glycerol and ethylene glycol) and acids. Meanwhile, results of Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis showed great differences in microbial population richness between cometabolic system and the control group. The Margalef’s richness index and Shannon-Wiener’s diversity index of microorganism in cometabolic system were 3.075 and 2.61, respectively. The results showed that extra addition of glucose, with a concentration of 943 mg/L, was beneficial to lignin biodegradation in cometabolic system.

Characterizing nonlinear oscillation behavior of an MRF variable rotational stiffness device

Yang Yu,Yancheng Li,Jianchun Li,Xiaoyu Gu 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.24 No.3

Magneto-rheological fluid (MRF) rotatory dampers are normally used for controlling the constant rotation of machines and engines. In this research, such a device is proposed to act as variable stiffness device to alleviate the rotational oscillation existing in the many engineering applications, such as motor. Under such thought, the main purpose of this work is to characterize the nonlinear torque-angular displacement/angular velocity responses of an MRF based variable stiffness device in oscillatory motion. A rotational hysteresis model, consisting of a rotatory spring, a rotatory viscous damping element and an error function-based hysteresis element, is proposed, which is capable of describing the unique dynamical characteristics of this smart device. To estimate the optimal model parameters, a modified whale optimization algorithm (MWOA) is employed on the captured experimental data of torque, angular displacement and angular velocity under various excitation conditions. In MWOA, a nonlinear algorithm parameter updating mechanism is adopted to replace the traditional linear one, enhancing the global search ability initially and the local search ability at the later stage of the algorithm evolution. Additionally, the immune operation is introduced in the whale individual selection, improving the identification accuracy of solution. Finally, the dynamic testing results are used to validate the performance of the proposed model and the effectiveness of the proposed optimization algorithm.

The Theoretical Calculations of Kinetic and Thermodynamics Parameters and Anharmonic Correction for the Related Reactions of NO₃

Yu, Hongjing,Liu, Yancheng,Xia, Wenwen,Wang, Li,Jiang, Meiyi,Hu, Wenye,Yao, Li Korean Chemical Society 2021 대한화학회지 Vol.65 No.6

According to the transition state (TS) theory, Gaussian software and Yao and Lin (YL) method, the thermodynamics and kinetic data respectively were calculated, and anharmonic effect was considered for related reactions of NO₃. The methods of calculating and fitting kinetic and thermodynamics parameters were provided by least square method and related equations in this paper. Notably, the fitted E of Arrhenius equation was close to the calculated barrier of related reaction by QCISD(T) method. Therefore, the kinetic fitting result can well express the physical meaning of E in Arrhenius equation. Besides, the conversion process and the reaction mechanism of NO₃ were researched. For NO₃, it seemed that its instability results from its easy reaction with other substances rather than the decompose reaction of itself.