Post-earthquake track irregularity spectrum of high-speed railways continuous girder bridge

Yulin Feng,Lizhong Jiang,Wangbao Zhou,Mengcheng Chen 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.40 No.3

To study the track irregularity spectrum for CRTS II ballastless track continuous girder bridge for high-speed railway (CBTCGB) after the action of earthquake, a line-bridge integration seismic calculation model was established. By considering the randomness of structural parameters and ground motion, large amounts of samples were analyzed for additional track irregularity caused by factors such as earthquake-induced damage and earthquake-induced void of key components between the layers of track-bridge system. Using improved Blackman-Turkey method and Levenberg- Marquardt algorithm, the earthquake damaged CBTCGB track irregularity spectrum, track irregularity spectrogram, and a fitting formula for track irregularity spectrum after the action of near-field earthquake were obtained, and the calculation results obtained from the fitting formula and CBTCGB numerical model were compared. The results indicate that the probability sampling distribution of ground motion and structural parameters selected according to “binning method” can effectively reflect the randomness of ground motion and structural parameters. The track irregularity spectrum line forms can be roughly divided into three ranges, namely, high-frequency, medium-frequency, and low-frequency waveband. The tracks suffer more track irregularity diseases with high-frequency after earthquake, which is necessary to conduct tracking analysis. It is rational to use a three-segment power function for the fitting of track irregularity spectrum after the action of earthquake.

A new metagenome binning method based on gene uniqueness

Yulin Kang,Cheng Wan,Sifen Lu,Zhehan Fu,Antony K. Chen,Zuhong Lu 한국유전학회 2020 Genes & Genomics Vol.42 No.8

Background The human gut microbiome contains millions of genes and many undetected bacteria species. Recovering bacterial genomes from large complex metagenomes remains highly challenging, and current binning methods show insufficient recall rates. Objective This study was performed to put forward a new metagenome binning method with promising recall rate and accuracy. Methods We found that more than 85% of the genes could be aligned to only one bacteria species by using strict BLAST parameters (identity > 90% and aligning length > 100 bp). This phenomenon was called “the gene uniqueness”, which indicated that the most bacterial genes could be exclusive to the species’ taxonomy. In our new metagenome binning method, we could cluster contigs based on gene similarity via a graph model. Any contig shared with same gene under Strict Blast parameters would be clustered into one bin. Results we obtained 1,131 bins and reconstructed the genomes of 12 unknown species for MetaHIT data Our method exhibited a more promising recall rate, faster running speed and lower time complexity than the current methods. Conclusions The present new metagenome binning method based on gene uniqueness had high recall rate and low error, which could be applied to assemble the bacterial genomes efficiently in complex metagenome.

Performance of Rock-like Materials Containing Filled Kinked Fissures under Uniaxial Tension at Failure

Yulin Wu,Qianqian Dong,Jian He,Qiyang Chen 대한토목학회 2023 KSCE JOURNAL OF CIVIL ENGINEERING Vol.27 No.3

To investigate the tensile failure phenomenon of rock masses with filled natural defects, the mechanical behavior of 3D printed rock-like materials containing filled kinked fissures under uniaxial tension was identified. Different inclination angles of branch fissure were considered, and cement and gypsum slurry were selected as the infilling materials. It was found that filling materials enhanced the strength of the specimen, which presented to be cement filling > gypsum filling > no filling. The change of inclination angle of branch fissure had significant influence on the strength and failure mode of the specimen and the strength order was -135o> -45o > 90o and +45o > 90o > +135o. Two types of failure pattern, namely tip failure and non-tip failure, were observed in the experiment. Three types of newborn cracks were identified using a high-speed camera. The result achieved by using the digital image correlation technology indicated that different filling conditions led to the position change of high-strain zone. The displacement field of the filled specimen developed from being continuous to being discontinuous. Furthermore, the extended finite element method was adopted to simulate the filled and unfilled specimens, consistent with the experimental results. This study can provide a reliable reference for studying the tensile stress zones in rock exploration.

The combination of deoxynivalenol and zearalenone at permitted feed concentrations causes serious physiological effects in young pigs

Feng Chen,Yulin Ma,Chunyi Xue,Jingyun Ma,Qingmei Xie,Genhu Wang,Yingzuo Bi,Yongchang Cao 대한수의학회 2008 JOURNAL OF VETERINARY SCIENCE Vol.9 No.1

This study was to investigate the effects of the combination of deoxynivalenol (DON) and zearalenone (ZON) on pigs. Twenty-four weaning piglets were divided into a control group fed a diet free of mycotoxins and a toxin group fed a diet containing 1 mg/kg DON and 250 μg/kg ZON. The results showed that supplementation of DON and ZON in diets had extensive effects on pigs. More specifically, DON and ZON caused levels of total protein, albumin, and globulin in sera to decrease (p < 0.05) by 14.5%, 6.5% and 11.3%, respectively, and at the same time increased (p < 0.05) the serum enzyme activities of γ-glutamyltransferase, aspartate aminotransferase and alanine aminotransferase by 72.0%, 32.6% and 36.6%, respectively. In addition, DON and ZON decreased (p < 0.05) the level of anticlassical swine fever antibody titers by 14.8%. Real-time PCR showed that DON and ZON caused the mRNA expression levels of IFN-γ, TNF-α, IL-2, to decrease (p < 0.05) by 36.0%, 29.0% and 35.4%, respectively. Histopathological studies demonstrated that DON and ZON caused abnormalities in the liver, spleen, lymph nodes, uterus, and kidney. The concentrations of DON and ZON used in this study are in line with the published critical values permitted by BML. Our study clearly put the standard and adequacy of safety measures for these toxins into question. The authors suggest that with the increasing availability of cellular and molecular technologies, it is time to revisit the safety standards for toxins in feeds so as to make feeds safer, providing consumers with safer products. This study was to investigate the effects of the combination of deoxynivalenol (DON) and zearalenone (ZON) on pigs. Twenty-four weaning piglets were divided into a control group fed a diet free of mycotoxins and a toxin group fed a diet containing 1 mg/kg DON and 250 μg/kg ZON. The results showed that supplementation of DON and ZON in diets had extensive effects on pigs. More specifically, DON and ZON caused levels of total protein, albumin, and globulin in sera to decrease (p < 0.05) by 14.5%, 6.5% and 11.3%, respectively, and at the same time increased (p < 0.05) the serum enzyme activities of γ-glutamyltransferase, aspartate aminotransferase and alanine aminotransferase by 72.0%, 32.6% and 36.6%, respectively. In addition, DON and ZON decreased (p < 0.05) the level of anticlassical swine fever antibody titers by 14.8%. Real-time PCR showed that DON and ZON caused the mRNA expression levels of IFN-γ, TNF-α, IL-2, to decrease (p < 0.05) by 36.0%, 29.0% and 35.4%, respectively. Histopathological studies demonstrated that DON and ZON caused abnormalities in the liver, spleen, lymph nodes, uterus, and kidney. The concentrations of DON and ZON used in this study are in line with the published critical values permitted by BML. Our study clearly put the standard and adequacy of safety measures for these toxins into question. The authors suggest that with the increasing availability of cellular and molecular technologies, it is time to revisit the safety standards for toxins in feeds so as to make feeds safer, providing consumers with safer products.

Effect of Bias Magnetic Field on Magnetoelectric Characteristics in Magnetostrictive/Piezoelectric Laminate Composites

Lei Chen,Yulin Luo 한국자기학회 2015 Journal of Magnetics Vol.20 No.4

The magnetoelectric (ME) characteristics for Terfenol-D/PZT laminate composite dependence on bias magnetic field is investigated. At low frequency, ME response is determined by the piezomagnetic coefficient d33,m and the elastic compliance S<SUP>H</SUP>33 of magnetostrictive material, d33,m and S<SUP>H</SUP>33 for Terfenol-D are inherently nonlinear and dependent on Hdc, leading to the influence of Hdc on low-frequency ME voltage coefficient. At resonance, the mechanical quality factor Qm dependences on Hdc results in the differences between the low-frequency and resonant ME voltage coefficient with Hdc. In terms of ΔE effect, the resonant frequency shift is derived with respect to the bias magnetic field. Considering the nonlinear effect of magnetostrictive material and Qm dependence on Hdc, it predicts the low-frequency and resonant ME voltage coefficients as a function of the dc bias magnetic field. A good agreement between the theoretical results and experimental data is obtained and it is found that ME characteristics dependence on Hdc are mainly influenced by the nonlinear effect of magnetostrictive material.

Digitally Current Controlled DC-DC Switching Converters Using an Adjacent Cycle Sampling Strategy

Tingcun Wei,Yulin Wang,Feng Li,Nan Chen,Jia Wang 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.1

A novel digital current control strategy for digitally controlled DC-DC switching converters, referred to as Adjacent Cycle Sampling (ACS), is proposed in this paper. For the ACS current control strategy, the available time interval from sampling the current to updating the duty ratio, is approximately one switching cycle. In addition, it is independent of the duty ratio. As a result, the contradiction between the processing speed of the hardware and the transient response speed can be effectively relaxed by using the ACS current control strategy. For digitally controlled buck DC-DC switching converters with trailing-edge modulation, digital current control algorithms with the ACS control strategy are derived for three different control objectives. These objectives are the valley, average, and peak inductor currents. In addition, the sub-harmonic oscillations of the above current control algorithms are analyzed and eliminated by using the digital slope compensation (DSC) method. Experimental results based on a FPGA are given, which verify the theoretical analysis results very well. It can be concluded that the ACS control has a faster transient response speed than the time delay control, and that its requirements for hardware processing speed can be reduced when compared with the deadbeat control. Therefore, it promises to be one of the key technologies for high-frequency DC-DC switching converters.

Numerical Simulation of the Coalescence Behavior of Intermittent Structures with Fissures

Qianqian Dong,Yulin Wu,Qiyang Chen 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.4

To further study the failure behavior of the rock-like materials containing intermittent fissures subjected to uniaxial compression, 3D printing technology was adopted to manufacture specimens with prefabricated kinked and straight fissures (K-S fissure). The order of average peak strength was -45o > -90o > +90o > +45o. The influence of different parameters, including the effective length and inclination angle of branch fissure, on the coalescence pattern was discussed. Results showed that two failure modes were observed: Model I represented tensile-shear composite failure in the rock bridge area, while Model II showed non-coalescence occurring. The effective length parameter presented a relatively larger influence than the inclination angle on the failure behavior. Additionally, Model I was discovered to tend to occur in the rock bridge region when the branch fissure turned anticlockwise. Based on numerical simulation using the Realistic Failure Process Analysis (RFPA2D), a quick damage criterion approach was proposed to estimate the coalescence behavior in the rock bridge, which was beneficial to determine coalescence pattern and failure behavior. Based on the curve fitted by the simulation, the coalescence pattern of cracks initiated from pre-existing intermittent fissures occurs in the tensile-shear composite fracture pattern, while non-coalescence occurs in the rock bridge below the curve.

Surveillance of Antimicrobial Susceptibility Patterns among Shigella Species Isolated in China during the 7-Year Period of 2005-2011

Haifei Yang,Guosheng Chen,Yulin Zhu,Yanyan Liu,Jun Cheng,Li-Fen Hu,Ying Ye,Jia-Bin Li 대한진단검사의학회 2013 Annals of Laboratory Medicine Vol.33 No.2

Background: Shigella is a frequent cause of bacterial dysentery in the developing world. Treatment with antibiotics is recommended for shigellosis, but the options are limited due to globally emerging resistance. This study was conducted to determine the frequency and pattern of antimicrobial susceptibility of Shigella in China. Methods: We studied the antimicrobial resistance profiles of 308 Shigella spp. strains (260S. flexneri, 40 S. sonnei, 5 S. boydii, and 3 S. dysenteriae) isolated from fecal samples of patients (age, from 3 months to 92 yr) presenting with diarrhea in different districts of Anhui,China. The antimicrobial resistance of strains was determined by the agar dilution method according to the CSLI guidelines. Results: The most common serogroup in the Shigella isolates was S. flexneri (n=260, 84.4%),followed by S. sonnei (n=40, 13.0%). The highest resistance rate was found for nalidixic acid (96.4%), followed by ampicillin (93.2%), tetracycline (90.9%), and trimethoprim/sulfamethoxazole (80.8%). Among the isolates tested, 280 (91.0%) were multidrug resistant (resistant to ≥2 agents). The most common resistance pattern was the combination of ampicillin,tetracycline, and trimethoprim/sulfamethoxazole (70.8%). Resistance to ampicillin and tetracycline were more common among S. flexneri than among S. sonnei isolates. Conclusions: S. flexneri is predominant in Anhui, China, and its higher antimicrobial resistance rate compared with that of S. sonnei is a cause for concern. Continuous monitoring of resistance patterns is necessary to control the spread of resistance in Shigella. The recommendations for antimicrobial treatment must be updated regularly based on surveillance results.

Digitally Current Controlled DC-DC Switching Converters Using an Adjacent Cycle Sampling Strategy

Wei, Tingcun,Wang, Yulin,Li, Feng,Chen, Nan,Wang, Jia The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.1

A novel digital current control strategy for digitally controlled DC-DC switching converters, referred to as Adjacent Cycle Sampling (ACS), is proposed in this paper. For the ACS current control strategy, the available time interval from sampling the current to updating the duty ratio, is approximately one switching cycle. In addition, it is independent of the duty ratio. As a result, the contradiction between the processing speed of the hardware and the transient response speed can be effectively relaxed by using the ACS current control strategy. For digitally controlled buck DC-DC switching converters with trailing-edge modulation, digital current control algorithms with the ACS control strategy are derived for three different control objectives. These objectives are the valley, average, and peak inductor currents. In addition, the sub-harmonic oscillations of the above current control algorithms are analyzed and eliminated by using the digital slope compensation (DSC) method. Experimental results based on a FPGA are given, which verify the theoretical analysis results very well. It can be concluded that the ACS control has a faster transient response speed than the time delay control, and that its requirements for hardware processing speed can be reduced when compared with the deadbeat control. Therefore, it promises to be one of the key technologies for high-frequency DC-DC switching converters.

The Development of a 20MW PWM Driver for Advanced Fifteen-Phase Propulsion Induction Motors

Chi Sun,Sheng Ai,Liangdeng Hu,Yulin Chen 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.1

Since the power capacity needed for the propulsion of large ships is very large, a multiphase AC induction propulsion mode is generally adopted to meet the higher requirements of reliability, redundancy and maintainability. This paper gives a detailed description of the development of a 20MW fifteen-phase PWM driver for advanced fifteen-phase propulsion induction motors with a special third-harmonic injection in terms of the main circuit hardware, control system design, experiments, etc. The adoption of the modular design method for the main circuit hardware design can make the enclosed mechanical structure simple and maintainable. It can also avoid the larger switch stresses caused by the multiple turn on of the IGBTs in conventional large-capacity converter systems. The use of the distributed controller design method based on a high-speed fiber-optic ring net for the control system can overcome such disadvantages as the poor reliability and long maintenance times arising from the conventional centralized controller which is designed according to point-to-point communication. Finally, the performance of the 20MW PWM driver is verified by experimentation on a new fifteen-phase induction propulsion motor.