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A new device for restraining rail vibration of ballastless track and its effect study
Zhenxing He,Xu Zhang,Xiaotao Wang,Hualong Zhou,Quanbao Feng,Qingchao Chen,Junxia Chen,Yanbo Bai,Runxi Zhang,Nengneng Bao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.8
A new type of rail vibration damping device (NTRVDV), which is arranged between the bottom of the rail and track bed, is proposed in this paper. The finite element model of the rail system with the NTRVDV and tuned rail damper (TRD) was established, respectively. The impact load was applied to the finite element model, and comparison of the set of existing TRD and NTRVDV on the dynamic response of rail and rail vibration decay rate. The effect of the stiffness change of the elastic layer of the NTRVDV on the rail vibration was studied, and a hammering test verified the theoretical research results. The research results show that compared with the traditional TRD, the NTRVDV has a more obvious suppression effect on rail vibration acceleration. The rail vibration decay rate is significantly improved, especially in the low-frequency stage. With the increase of the stiffness of the elastic layer of the vibration suppression device, the vibration suppression effect of the NTRVDV on the rail is improved. The change of the elastic layer stiffness significantly impacts the rail’s vibration suppression effect in the range of 0-7 kN/mm.
Ultrafast UV Switch Based on ZnO-Ag Heterostructures
XIU-YUN AN,Feng Teng,Zhenxing Zhang,Xiaojun Pan,Jinyuan Zhou,ER-QING XIE 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.1
ZnO-silver (Ag) heterostructure nanoparticle films were prepared by spin-coating, followed by annealing at 700°C for 2 h. The films were then used as UV photodetector which show high photoresponse. The heterostructure-film device displayed an ultrafast decay time of 18 ms and a rise time of 50 ms upon ultraviolet irradiation. Additionally, the time-dependent photocurrent upon UV switching reveals a rectangularly shaped profile, rarely reported in previous literature. The highly improved photoresponse properties of ZnO-Ag heterostructure-film device could be attributed to the Schottky barrier height (SBH) and depletion width reduction from the embedded Ag nanoclusters. Compared to a pure ZnO film, both the responsivity (Rλ) and external quantum efficiency (EQE) of the ZnO-Ag heterostructure-film photodetectors were improved more than 13-fold. This research provides a promising strategy for fabricating UV-photodetectors with ultrafast response.
이지은,장유진,( Wenqian Xu ),( Zhenxing Feng ),박희영,김진영,김동하 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0
The design of cost-effective and efficient catalysts requires not only reduced usage of precious metals such as Pt, but also enhanced catalytic activity and stability, which are important for efficient catalysts of the electrode on both anode and cathode. Composites consisting of functional polymers and metal nanoparticles (NPs) are of great interest due to their combined properties with improved dispersion of metal NPs and high surface area. Consequently, we suggest novel core@shell NPs based on AuNPs decorated with conducting polymer which can serve as templates for tailored nanostructures. The PtNPs thus incorporated were distributed uniformly in the polymer shells. We systematically investigated the structural development during the synthetic process and compared the performance with respect to metallic core-shell nanostructures, which showed a viable and efficient electrocatalytic activity for both anode and cathode in electrodes of the fuel cell.
Pressure-Induced Confined Metal from the Mott InsulatorSr3Ir2O7
Ding, Yang,Yang, Liuxiang,Chen, Cheng-Chien,Kim, Heung-Sik,Han, Myung Joon,Luo, Wei,Feng, Zhenxing,Upton, Mary,Casa, Diego,Kim, Jungho,Gog, Thomas,Zeng, Zhidan,Cao, Gang,Mao, Ho-kwang,van Veenendaal, American Physical Society 2016 Physical Review Letters Vol.116 No.21
<P>The spin-orbit Mott insulator Sr3Ir2O7 provides a fascinating playground to explore insulator-metal transition driven by intertwined charge, spin, and lattice degrees of freedom. Here, we report high-pressure electric resistance and resonant inelastic x-ray scattering measurements on single-crystal Sr3Ir2O7 up to 63-65 GPa at 300 K. The material becomes a confined metal at 59.5 GPa, showing metallicity in the ab plane but an insulating behavior along the c axis. Such an unusual phenomenon resembles the strange metal phase in cuprate superconductors. Since there is no sign of the collapse of spin-orbit or Coulomb interactions in x-ray measurements, this novel insulator-metal transition is potentially driven by a first-order structural change at nearby pressures. Our discovery points to a new approach for synthesizing functional materials.</P>