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Research on influence of harmonic wear wheel on wheel/rail contact geometry of high-speed train
Qian Xiao,Zhixiang Luo,Xu Xu,Jifeng Zheng,Shu Cheng 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.2
Harmonic wear is one of the common wear phenomena of high-speed train wheels. The change of wheel/rail rolling contact geometry leads to unstable characteristics of wheel/rail contact, which directly affects the quality and safety of high-speed train operation. Because wheelset lateral displacement directly affected the wheel/rail contact geometry, in this paper, the UM software was used to establish a high-speed train vehicle-track coupled dynamics simulation model of the CRH2 (China Railway High-speed 2) head car. Lateral displacement of harmonic wear wheel was calculated under different wear condition to analyze the influence of harmonic wear wheels on wheelset lateral displacement. Then according to macroscopic dimension change of the wheel profile from lateral and radial directions of high-speed train induced by harmonic wear wheels, wheel profiles under different wear condition were selected. And wheel/rail contact geometry under different harmonic wear stages was calculated to discuss the influence of harmonic wear wheel on wheel/rail contact geometry. The results show that harmonic order and wave depth of harmonic wear wheel have small influence on the lateral displacement of wheelset, but the influence of wave depth is greater than harmonic order. The average difference of lateral displacement between harmonic wear wheel and no harmonic wear wheel increases with the increase of wave depth and order. In a harmonic wave length, the maximum value of both equivalent conicity and contact angle appear in deepest wave depth. The greater the wave depth, the more obvious the fluctuations, and equivalent conicity changes are less obvious.
Wind Tunnel Test of Wind Load on a Typical Cross Line High-Speed Railway Station
Lei Zhao,Zhixiang Yu,Xin Qi,Hu Xu 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.10
In order to study the influence of the layout of station buildings on the wind field characteristic, wind tunnel tests of wind load on the main roof and platform canopy of the Jinan West Railway Station are presented in this paper. Four 1:250-scale rigid models of the station with different characteristics were made. Not only the wind loading of the first phase station, but also the interference effect of the extension of the second phase station, the longitudinal gap of the platform canopy and the blocking rate of the interchange corridor on wind loading of the station were studied. The results show that the station roof, especially the overhanging eave mainly subjected to wind suction. Although the longitudinal gap of the platform canopy increases the turbulence intensity, the wind pressure on the upper and lower surface of the platform canopy tend to weaken each other. The extension of the second phase station will change the wind load characteristic of the first phase station roof and platform canopy obviously. Under specific wind angle, wind loading on large area of the platform canopy will change from wind suction to wind pressure. With the increase of blocking rate of the interchange corridor, both the wind pressure and wind suction of the platform canopy will be intensified.
Chengtang Liu,Huaming Li,Hui Xu,Ling Liu,Li Xu,Zhixiang Ye 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.4
Na_8Nb_6O_19.13H_2O particles were synthesized by a simple hydrothermal method. The catalysts were characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM) and thermogravimetric and differential scanning (TG-DSC). The XRD and TG-DSC analyses indicated that Na_8Nb_6O_19.13H-2O was an intermediate hexaniobate during the preparation of NaNbO_3 powders. Methylene blue (MB) dye degradation using Na_8Nb_6O_19.13H_2O/H_2O_2,Nb_2O_5/H_2O_2 and NaNbO_3/H_2O_2 systems were investigated, respectively. Among the catalytic oxidation systems, Na_8Nb_6O_19·13H_2O showed the highest activity for degradation of MB in the presence of H_2O_2. The results indicated that the dye degradation efficiency could be 93.5% at 30 ℃ after 60 min in the presence of the Na_8Nb_6O_19·13H_2O/H_2O-2 system. It was also found that the degradation of MB over the catalytic systems followed pseudo-first-order kinetics, and the degradation rate was 0.02376 min−1 in the Na_8Nb_6O_19.13H_2O/H_2O_2 system, which was higher than that in the Nb_2O_5/H_2O_2and NaNbO_3/H_2O_2 systems. A possible mechanism for MB catalytic oxidation degradation using the Na_8Nb_6O_19.13H-2O/H_2O_2 system was proposed.
Shengjia Huang,Xinya Liu,Bo Xiong,Xia Qiu,Guochao Sun,Xiaojia Wang,Xu Zhang,Zhixiang Dong,Zhihui Wang 한국식품과학회 2019 Food Science and Biotechnology Vol.28 No.3
The nomilin and limonin content in citrus fruitsof different varieties was determined at fruit growth andmaturation stages by HPLC. The results showed that thetwo limonoids can be separated, identified, and quantifiedin citrus fruits within 10 min by the developed method. Themethod exhibited good precision, repeatability, stability,and recovery rate. The content of limonin and nomilin inmost citrus fruits presented an increasing trend initially,and then decreased during fruit growth and maturation; apeak was observed at the young fruit or fruit expansionstage. The dropped fruits also contained some amount oflimonoids, suggesting their industrial application. Thevariation and cluster analyses results revealed that theorange varieties contained the highest amount of limonoidsat the mature stage. The results of this study will enablebetter use of citrus limonoids.
Kuiling Zu,Jianxia Li,Shubin Dong,Yunyu Zhao,Shenjian Xu,Zhixiang Zhang,Liangcheng Zhao 한국유전학회 2017 Genes & Genomics Vol.39 No.6
As a specialized seed appendage, the aril is a noteworthy and taxonomically important feature of Celastrus orbiculatus; the aril also has important ornamental value and biological functions. To better understand the mechanism of aril development, paraffin sections were used to examine its morphogenesis, and RNA-sequencing (RNA-seq) technology was employed for transcriptional profiling of the developing aril. Our results revealed that the aril of C. orbiculatus was formed by the cells of the exostomal region of the outer integument. By analyzing global changes in the transcriptome, 41,560,806, 42,789,340, and 44,496,748 clean reads from three cDNA libraries were generated and assembled into 87,600 unigenes with N50 of 1328 bp, in which 31,971 (36.49%) were annotated to Nr database. Furthermore, a total of 25,914 (29.79%), 14,394 (16.4%) and 11,957 (13.65%) genes were successfully annotated with hierarchical 48 GO terms, 26 KOGs and 32 KEGG pathways. Totally, 104, 1887 and 1967 differently expressed genes were identified in CO-F2 versus CO-F3, CO-F2 versus CO-YF1 and CO-F3 versus CO-YF1, respectively. GO and KEGG pathway analyses of DEGs involved in cell–cell communication and plant hormone signal transduction contributed to aril development were identified. Furthermore, we found putative key target genes of WRKY, Aux/IAA, ARF and MADS-box family’s transcription factors related to aril development. Real-time qPCR was performed on eight genes randomly selected from important transcription factors to validate the expression profiles obtained by RNA-seq. This work provides a platform for future genetic and functional genomics research on the molecular mechanisms of aril structure, and expands our understanding of the molecular mechanism and evolutionary analysis of aril development in other members of the Celastraceae.