Bending performance of NSTS members based on steel tube connection

Xueliang Zhang,Lianguang Wang,Bailing Chen,Yaosheng Zhang 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.41 No.1

This paper proposes a NSTS (new steel tube slab) structure by connecting the longitudinal steel tubes with small steel tubes in transverse, in order to decrease the construction difficulty and improve the bearing capacity of existing NTR (new tubular roof) or STS (steel tube slab) structures. Experimental study on the bending performance and influences of following parameters are carried out: the connection type of the steel tube, the diameter and eccentricity of the small steel tube, and the thickness of the bottom steel plate. The results show that the NSTS members present progressive ductile flexural failure under concentrated load. The connection type has important effect on the mechanical behavior, and the bolts fixed T-shaped plate (B+T) connection method, which provides much higher bending stiffness, is proved to be the most reliable connection type. The increase of small steel tube diameter enhances the bending performance as expected, which also confirms the effectiveness of the B+T connection, while the tube eccentricity presents little impact on the bearing capacity. The bottom steel plate significantly improves the bearing capacity and stiffness and reduces the mid-span deflection. Furthermore, the bending capacity calculation method is proposed and the calculated values show good agreement with the test results. Also, the effect rules of the diameter-thickness ratio of the small tube, the length-diameter ratio of the member and the thickness variety of the bottom steel plate on the bending capacity of NSTS members are further investigated based on the proposed theoretical method.

Vibratory synchronization transmission of two exciters in a super-resonant vibrating system

Xueliang Zhang,Bang-chun Wen,Chunyu Zhao 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.6

In this study, vibratory synchronization transmission (VST) of two exciters is investigated in a super-resonant vibrating system to saveenergy. First, the frequency capture equation of two exciters (FCETE) is deduced by the average method of small parameters. The criterionof VST being the equivalent effective residual torque of motor with power supply should be smaller or equal to the frequency capturetorque of the system by setting the disturbance parameters of angular velocities in FCETE to zero. The stability criterion of synchronousstates is derived by complying with the generalized Lyapunov equations. Lastly, experiment and computing simulation on VST areconducted. The VST regime of two exciters is discussed in detail from coupling characteristic, current change, visual picture, phase relation,and direct verification of parameters, respectively by comparison and analyses of corresponding data. Results indicate that the keyfactor in VST implementation is the torque of frequency capture, which serves as the ‘vehicle’ in transferring energy. Thus, the distancebetween rotational centre of each exciter and mass centre of the rigid frame should be far enough to enhance the ability of VST and ensureenergy saving. The theory, experiment, and computing simulation prove that the theoretical approach used in this study is useful and feasible.

Comments on the stability of the synchronous states of three vibrators in a vibrating system with two rigid frames

Xueliang Zhang,Zhihui Wang,Chao Li,Jinlin Xu 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.10

This paper focuses on the stability of three homodromy vibrators in a vibrating system with two rigid frames (RFs). The motion differential equations of the system are established. Using the average method yields the average coupling torque balanced equations of three vibrators, and the simplified analytical expressions for synchronization and stability criterions of the system were derived. The coupling dynamic characteristics were numerically analyzed, including frequency-amplitude response, stable phase differences, synchronization and stability ability, and phase relationships. The simulations to verify the validity of theoretical results were carried out. It is shown that the stable states of the system are classified into three types, thereof the stability of phase differences among vibrators is similar in sub-resonant and super-resonant states, which results in no vibration of the system. While in near sub-resonant state the system reflects strong useful positive superposition vibration with energy saving, which is exactly the desire in engineering design.

Facile Fabrication and Characterization of Ytterbium Oxide Hollow Spheres using Carbon Spheres as Template

Xueliang Jiang,Lu Yu,Chu Yao,Feng You,Jiao Zhang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.6

Uniform rare-earth ytterbium oxide (Yb2O3) hollow microspheres have been successfully prepared via a urea-based homogenous precipitation method using carbon spheres as template, followed by a heat treatment. The main synthesis process was carried out in aqueous conditions without any organic solvents, surfactants or etching agents. X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetry, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller surface area measurement were employed to characterize the samples. The results show that the final products can be indexed to cubic Yb2O3 phase with high purity. The as-obtained Yb2O3 microspheres with spherical shape and hollow structure are uniform in size and distribution of about 450 nm and wall thickness of approximately 15 nm.

Correlation analysis and prognostic value of miR-29a-3p expression and CYP2C19 genotypes in exfoliated cells from tongue coating of patients with gastroesophageal reflux disease

Zhang Aiqing,Liu Wenjuan,Niu Lingyun,Zhu Liping,Yang Liuqing,Li Xueliang 한국유전학회 2023 Genes & Genomics Vol.45 No.5

Background Gastroesophageal reflux disease (GERD) is a highly prevalent and troublesome disease. Several differentially expressed microRNAs (miRNAs) have been found in GERD. Objective This study was to analyze the correlation of miR-29a-3p expression and CYP2C19 genotypes in exfoliated cells from tongue coating of GERD patients and its prognostic value. Methods Tongue coating specimens were collected from 130 GERD patients and 70 healthy volunteers and their clinical baseline information was recorded. miR-29a-3p expression in exfoliated cells from tongue coating was determined via RT-qPCR, and its diagnostic efficiency on GERD was evaluated via receiver operating characteristic curve. CYP2C19 genotypes and their correlation with miR-29a-3p were analyzed via polymerase chain reaction restriction fragment length polymorphism technique. The adverse events of patients were documented via 12-month follow-up. The impact of miR-29a-3p expression on the healing rate of patients was analyzed via Kaplan-Meier method. Qualification of miR-29a-3p as an independent prognostic factor of GERD patients was analyzed via multivariate Cox regression analysis. Results miR-29a-3p was highly-expressed in exfoliated cells from tongue coating of GERD patients. miR-29a-3p expression had high specificity and sensitivity in diagnosing GERD. CYP2C19 genotypes in GERD patients comprised rapid metabolizers, intermedia metabolizers, and poor metabolizers. miR-29a-3p expression showed a correlation with CYP2C19 genotypes. Higher miR-29a-3p expression predicted higher cumulative incidences of adverse outcomes. Highly-expressed miR-29a-3p was an independent prognostic factor for adverse outcomes of GERD patients. Conclusion High expression of miR-29a-3p aided the diagnosis and predicted poor prognosis of GERD patients.

Dynamic Event-triggered Adaptive Control for Uncertain Nonlinear Switched Systems Based on MDADT Method

Xueliang Wang,Jianwei Xia,Na Zhang,Miao Yu,Xiaoxiao Guo 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.1

This article deals with the dynamic event-triggered tracking control problem for nonlinear switched systems with uncertain nonlinearities. By combining neural network control technology, mode-dependent average dwell time (MDADT) switching rule and dynamic event-triggered strategy, a valid adaptive control scheme is established, which guarantees the boundedness of all signals in the resulting closed-loop system and the tracking error eventually converges to a small neighborhood of the origin under a class of switching signals with MDADT property. Unlike the existing tracking control schemes, the proposed dynamic event-triggered strategy reduce some unnecessary transmissions from controller to actuator and thus saving network resources better. Finally, the effectiveness of the proposed control design is verified by a numerical simulation.

Modeling of normal stiffness of mechanical joint based on anisotropic fractal theory

Wan Sun,Guosheng Lan,Xueliang Zhang 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.8

An idealized model of elliptical asperities was constructed by combining the geometric features of asperities on rough surfaces with the bivariate Weierstrass-Mandelbrot function for junction surfaces with anisotropic fractal characteristics. Based on the Hertz contact theory, the elastic and plastic contact properties of elliptical asperities were studied. It was assumed that the contact point area distribution, eccentricity distribution, and angle distribution of the mechanical joint are independent of each other. According to probability theory and the area size distribution function of the contact point, the three-dimensional joint distribution density functions of the area distribution, eccentricity distribution and angle distribution of the contact point were obtained. By extending the contact characteristics of a single asperity to the entire mechanical joint, a normal contact stiffness model of the mechanical joint was established. The influence of fractal parameters and material parameters on the normal contact stiffness of the mechanical joint was discussed by numerical simulation. Finally, the validity of the model was verified by comparing with the classical model and experimental data.

Effect of Resin Coating and Sand Gluing on Interface Properties between Polypropylene Fibers and Concrete

Guyu Feng,Xinyue Wang,Diantang Zhang,Xueliang Xiao,Kun Qian 한국섬유공학회 2020 Fibers and polymers Vol.21 No.7

This paper presents the results of resin coating and sand gluing on the acoustic emission (AE) characteristics in theinterface failure process of concrete reinforced by polypropylene (PP) fibers. Interface property is an important performanceof fibers reinforced concrete, and the pull-out test is the simplest and most effective mean to investigate interface behaviorbetween concrete and fibers. In this study, the realistic bi-linear local bond-slip law and the AE results are employed in thiswork to derive expressions of interface stress distribution and present the detailed analysis. The results of AE test are used toexplain interface stress propagation in the different loading stages. Interface failure energy is also described quantitatively fordifferent interface mode in this work.

Effect of Restricted Grazing Time on the Foraging Behavior and Movement of Tan Sheep Grazed on Desert Steppe

Chen, Yong,Luo, Hailing,Liu, Xueliang,Wang, Zhenzhen,Zhang, Yuwei,Liu, Kun,Jiao, Lijuan,Chang, Yanfei,Zuo, Zhaoyun Asian Australasian Association of Animal Productio 2013 Animal Bioscience Vol.26 No.5

To investigate the effect of restricted grazing time on behavior of Tan sheep on desert steppe, forty 4-months old male Tan sheep with an original body weight (BW) of $15.62{\pm}0.33$ kg were randomly allocated to 4 grazing groups which corresponded to 4 different restricted grazing time treatments of 2 h/d (G2), 4 h/d (G4), 8 h/d (G8) and 12 h/d (G12) access to pasture. The restricted grazing times had a significant impact on intake time, resting time, ruminating time, bite rate and movement. As the grazing time decreased, the proportion of time spent on intake, bite rate and grazing velocity significantly (p<0.05) increased, but resting and ruminating time clearly (p<0.05) decreased. The grazing months mainly depicted effect on intake time and grazing velocity. In conclusion, by varying their foraging behavior, Tan sheep could improve grazing efficiency to adapt well to the time-limited grazing circumstance.

Sequence Analysis and Molecular Characterization of Wnt4 Gene in Metacestodes of Taenia solium

Junling Hou,Xuenong Luo,Shuai Wang,Cai Yin,Shaohua Zhang,Xueliang Zhu,Yongxi Dou,Xuepeng Cai 대한기생충학열대의학회 2014 The Korean Journal of Parasitology Vol.52 No.2