The Analysis on the Influence of Risk Perception on Behavioral Intention of Cycling into Tibet

( Tao Song ),( Shulin Liu ) 아시아스포츠융합과학회 2020 Asia Pacific Journal of Applied Sport Sciences Vol.1 No.3

PURPOSE The purpose of this study is to establish a structural equation model of the influence of risk perception on satisfaction and behavioral intention of cycling into Tibet, and to verify the relationship between natural risk, social risk, cultural risk, organizational risk, satisfaction and behavioral intention. METHOD Taking cycling into Tibet as the background, people cycling into Tibet in the past three years were taken as the main research samples. A total of 380 questionnaires were collected online for research and analysis through the WJX questionnaire network platform. Descriptive statistics, exploratory factor analysis, confirmatory factor analysis and structural equation model were used to analyze the collected data. RESULT The results showed that (1) cyclists cycling into Tibet were engaged in serious leisure and their natural risk perception positively affected their behavioral intentions. (2) satisfaction was an important predictor of their behavioral intentions cycling into Tibet. (3) social, cultural and organizational risk negatively affected satisfaction. CONCLUSION Satisfaction is an important factor in the behavior intention of cycling into Tibet. The results of this study provided some practical suggestions for the organization and management of cycling into Tibet, as well as suggestions for future studies, such as theoretical supports for tourists' behavioral intentions like revisiting Tibet.

Research of the Synthesis and Film Performance of Silica/Poly(St-BA-MPS) Core-Shell Latexes Obtained by Miniemulsion co-Polymerization

Shixin Song,Hanxiao Lv,Yuanjing Bi,Shulin Sun,HuiXuan Zhang 한국고분자학회 2017 Macromolecular Research Vol.25 No.5

Colloid silica nanoparticles were hydrophobic modified by γ-methacryloxypropyl trimethoxysilane (MPS) for the encapsulation into polymer. The alkoxysilane- functionalized core-shell latexes were successfully synthesized via miniemulsion copolymerization of the butyl acrylate, styrene with MPS as the functional monomer in the presence of the modified silica. When these latexes dried at room-temperature, the post-cross-linking occurred due to the alkoxysilane groups on the particle surface and lead to the formation of the films. The morphology of the nanocomposite latexes and the mechanical properties, thermal properties, fire-resistant, optical properties and micro-structure of the resulted films were characterized and discussed. Scanning electron microscope result showed most of the nanoparticles dispersed homogeneously in the polymer matrix when the content of MPS-silica was 10%. However, when the content of MPS-silica nanoparticles was beyond 10%, the aggregation of the nanoparticles became obvious. The tensile test showed that the stress at break increased a lot with the increase of silica content. The thermal and fire-resistant behaviors of the nanocomposite films were improved greatly by the incorporation of silica particles. The optical test showed that the hybrid film was comparable to the pure polymer film at around 84% transmittance.

State trend prediction of hydropower units under different working conditions based on parameter adaptive support vector regression machine modeling

Guo Zhao,Shulin Li,Wanqing Zuo,Haoran Song,Heping Zhu,Wenjie Hu 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.9

To address the problem where the different operating conditions of hydropower units have a large influence on the parameters of the trend prediction model of the operating condition indicators, a support vector regression machine prediction model based on parameter adaptation is proposed in this paper. First, the Aquila optimizer (AO) is improved, and a sine chaotic map is introduced to influence the population initialization process. An improved adaptive weight factor is used to balance the local search and global search capabilities. Second, according to the power and the head, the operating conditions of the unit are refined into several typical sets of operating conditions. On this basis, an SVR model is established using the improved AO search algorithm proposed in this paper, and the prediction parameters under each of the operating condition are optimized to establish the data of the operating conditions and optimal parameters. Then a neural network is used to fit the working condition and the optimal prediction parameters. In addition, the nonlinear function mapping of the complex relationship between the two is constructed. Finally, the constructed mapping relationship is added to the traditional SVR, and an adaptive SVR prediction model suitable for changes in the working conditions of hydropower units is realized. Simulation results show that when compared to the traditional SVR prediction model, the adaptive SVR prediction model designed in this paper can automatically adjust the prediction parameters according to changes in the working conditions and achieve the goal of maintaining optimal prediction performance under different working conditions. In addition, it has the ability to accurately predict the development trend of the unit operating state index within a certain time scale.

Enhanced Properties of PBT/PC Blends with the Addition of Carboxyl-functionalized Multiwalled Carbon Nanotube

Yuanjiao Hu,Shixin Song,Xue Lv,Shulin Sun 한국고분자학회 2018 폴리머 Vol.42 No.2

Carboxyl-functionalized multiwalled carbon nanotube (c-MWCNT) was used to enhance the properties of poly(butylene terephthalate)/polycarbonate (PBT/PC) blends by melt blending. The c-MWCNT inhibited transesterification reactions between PBT and PC. SEM result showed that most of the c-MWCNT dispersed in the PBT matrix and partial c-MWCNT lied between the interface of PBT and PC phases. c-MWCNT promoted the crystallization of PBT due to the decreased transesterification and the heterogeneous nucleating effect, which led to a 20 oC increase of the crystallization temperature. DMA test indicated that the miscibility between PBT and PC decreased with the c-MWCNT loading since the inhibited transesterification. When the c-MWCNT content was 4 wt%, the yield strength of 65.9 MPa and tensile modulus of 2116MPa were achieved, which corresponded to 23.9 and 19.5% increase relative to the pure PBT/ PC blend. The conductivity and dielectric properties of PBT/PC were largely enhanced by the c-MWCNT. The σdc values of PBT/PC improved greatly by several orders of magnitude from 10-18 to 10-7 when the c-MWCNT content was 2 wt%. The dielectric constant at 100 Hz for the nanocomposites increased from 2.8 to 146 when the c-MWCNT loading varied from 0.1 to 4 wt%, which improved more than 50 times.

Dynamic behavior analysis of reciprocating compressor with subsidence fault considering flexible piston rod

Shungen Xiao,Hongli Zhang,Shulin Liu,Feng Jiang,Mengmeng Song 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.9

Subsidence wear is inevitable in a reciprocating compressor system, but how to induce body vibration is not clear. We investigated the dynamic behavior of a reciprocating compressor system with subsidence fault considering a flexible piston rod. The flexible piston rod was modeled as a cantilever beam. The dynamic model, in which the influence of the subsidence size, variational cylinder pressure, impact effects and piston rod flexibility are taken into account, was established. Influences of the four parameters including subsidence size, vertical force of flexible piston rod, cylinder pressure and crankshaft speed were analyzed in the dynamic response. Numerical results reveal that with the change of the four parameters, the existence of subsidence fault has a significant effect on the displacement, velocity and acceleration of the crosshead in the transverse direction, but only conspicuously affects the acceleration in the longitudinal direction. In addition to cylinder pressure, the larger the values of the other three parameters, the greater the influences. The cylinder pressure is a time-varying working load. Not only the cylinder pressure but also the open/close time of the valves and change rate of the pressure all affect the dynamic behavior of the system with subsidence. Meanwhile, the change in the vertical force of the flexible piston rod has a remarkable effect on the jump position of the crosshead, but the effect of other parameters is not obvious. In addition, the changes of parameters produce obvious influences on the impact force and the impact range of the crosshead. The stability of the reciprocating compressor system was studied using Poincaré portraits method. The result shows that the system with subsidence fault has chaotic behavior.

A reduced time-varying model for a long beam on elastic foundation under moving loads

Guiming Mei,Caijin Yang,Shulin Liang,Jiangwen Wang,Dong Zou,Weihua Zhang,Yunshi Zhao,Zhong Huang,Shuqi Song,Mengying Tan,Yao Cheng,Bingrong Miao 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.9

Dynamics of a long beam on the elastic foundation subjected to moving loads is studied in the present paper. The sliding window technique is used to dynamically truncate the long beam and a reduced time-varying beam system is obtained. The Hamilton’s principle is employed to establish the equations of motion of the reduced system. The variable separation method is adopted to solve dynamical responses of the reduced system. Examples of a long simply supported Timoshenko beam on the nonlinear foundation subjected to a single moving load and multiple loads are included. Numerical results of the reduced model compared with the ones obtained from the moving element model adapted in literature are carried out to show the validity and the good efficiency of the method proposed in the present paper.

Performance Improvement of Poly(vinylidene fluoride) by In Situ Copolymerization of Methyl Methacrylate and Ionic Liquid

Xiujie Bi,Shixin Song,Shulin Sun 한국고분자학회 2017 Macromolecular Research Vol.25 No.12

1-Butyl-3-vinylimdazolium tetrafluoroborate ([BVIM][BF4]) was used as ionic liquid to in situ copolymerized with methyl methacrylate (MMA) in poly(vinylidene fluoride) (PVDF) solution by the free radical polymerization method. The content of [BVIM][BF4] in the copolymerized monomers ranges from 0 to 50%. Soxhlet extraction results showed that more than 60% P(MMA-co-[BVIM][BF4]) were grafted onto the PVDF chains and the grafting degree was higher than 15%. 1H NMR tests proved the occurrence of grafting reaction. SEM morphology indicated that phase separation took place for the in situ PVDF/P(MMA-co-[BVIM][BF4]) composites when the [BVIM][BF4] content was more than 40wt%. FTIR and XRD measurements indicated the crystal transformation of PVDF from α-phase to β/γ phase due to the ion-dipole interaction between PVDF and [BVIM][BF4]. Furthermore, the introduction of [BVIM][BF4] into the in situ PVDF/P(MMA-co-[BVIM][BF4]) composites enhanced the electrical conductivity and dielectric constant of PVDF. The present method improved the stability of ionic liquid in the PVDF composites and the in situ PVDF/P(MMA-co-[BVIM][BF4]) composites show potential applications in sensor, actuator and battery fields.

Surface oxidation of PAN‑based ultrahigh modulus carbon fibers (UHMCFs) and its effect on the properties of UHMCF/EP composites

Xinyu Wang,Xin Qian,Yonggang Zhang,Xuefei Wang,Shulin Song,Cheng Zhang 한국탄소학회 2021 Carbon Letters Vol.31 No.3

In this study, nitric acid oxidation with varied treatment temperature and time was conducted on the surfaces of polyacrylonitrile- based ultrahigh modulus carbon fibers. Scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and surface tension/dynamic contact angle instruments were used to investigate changes in surface topography and chemical functionality before and after surface treatment. Results showed that the nitric acid oxidation of ultrahigh modulus carbon fibers resulted in decreases in the values of the crystallite thickness Lc and graphitization degree. Meanwhile, increased treating temperature and time made the decreases more obviously. The surfaces of ultrahigh modulus carbon fibers became much more activity and functionality after surface oxidation, e.g., the total surface energy of oxidized samples at 80 °C for 1 h increased by 27.7% compared with untreated fibers. Effects of surface nitric acid oxidation on the mechanical properties of ultrahigh modulus carbon fibers and its reinforced epoxy composites were also researched. Significant decreases happened to the tensile modulus of fibers due to decreased Lc value after the nitric acid oxidation. However, surface treatment had little effect on the tensile strength even as the treating temperature and processing time increased. The highest interfacial shear strength of ultrahigh modulus carbon fibers/epoxy composites increased by 25.7% after the nitric acid oxidation. In the final, surface oxidative mechanism of ultrahigh modulus carbon fibers in the nitric acid oxidation was studied. Different trends of the tensile strength and tensile modulus of fibers in the nitric acid oxidation resulted from the typical skin–core structure.