Dynamic analysis of coupled train - ladder track - elevated bridge system

Xia, He,Deng, Yushu,Xia, Chaoyi,De Roeck, G.,Qi, Lin,Sun, Lu Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.47 No.5

As a new type of vibration reduction, the ladder track system has been successfully used in engineering. In this paper, a numerical model of the train-track-viaduct system is established to study the dynamic responses of an elevated bridge with ladder track. The system is composed of a vehicle submodel, a track submodel and a bridge submodel, with the measured track irregularities as the system self-excitation. The whole time histories of a train running through an elevated bridge with $3{\times}27m$ continuous PC box girders are simulated. The dynamic responses of the bridge such as deflections, lateral and vertical accelerations, and the vehicle responses such as derailment factors, offload factors and car-body accelerations are calculated. The calculated results are partly validated through the comparison with the experimental data. Compared to the common slab track, adapting the ladder sleeper can effectively reduce the accelerations of the bridge girder, and also reduce the car-body accelerations and offload factors of the train vehicle.

Facile synthesis of manganese carbonate quantum dots/Ni(HCO₃)₂–MnCO₃ composites as advanced cathode materials for high energy density asymmetric supercapacitors

Xia, Qi Xun,San Hui, Kwan,Hui, Kwun Nam,Kim, Sung Dae,Lim, Jae Hong,Choi, Si Young,Zhang, Luo Jiang,Mane, Rajaram S.,Yun, Je Moon,Kim, Kwang Ho The Royal Society of Chemistry 2015 Journal of Materials Chemistry A Vol.3 No.44

<▼1><P>Well dispersed MnCO3 quantum dots (∼1.2 nm) decorated on Ni(HCO3)2–MnCO3 as a cathode electrode for high performance supercapacitors.</P></▼1><▼2><P>We have developed a high performance supercapacitor cathode electrode composed of well dispersed MnCO3 quantum dots (QDs, ∼1.2 nm) decorated on nickel hydrogen carbonate–manganese carbonate (Ni(HCO3)2–MnCO3) hedgehog-like shell@needle (MnCO3 QDs/NiH–Mn–CO3) composites directly grown onto a 3D macro-porous nickel foam as a binder-free supercapacitor electrode by a facile and scalable hydrothermal method. The MnCO3 QDs/NiH–Mn–CO3 composite electrode exhibited a remarkable maximum specific capacitance of 2641.3 F g<SUP>−1</SUP> at 3 A g<SUP>−1</SUP> and 1493.3 F g<SUP>−1</SUP> at 15 A g<SUP>−1</SUP>. Moreover, the asymmetric supercapacitor with MnCO3 QDs/NiH–Mn–CO3 composites as the positive electrode and graphene as the negative electrode showed an energy density of 58.1 W h kg<SUP>−1</SUP> at a power density of 900 W kg<SUP>−1</SUP> as well as excellent cycling stability with 91.3% retention after 10 000 cycles, which exceeded the energy densities of most previously reported nickel or manganese oxide/hydroxide-based asymmetric supercapacitors. The ultrahigh capacitive performance is attributed to the presence of the high surface area core–shell nanostructure, the well dispersed MnCO3 quantum dots, and the high conductivity of MnCO3 quantum dots as well as the synergetic effect between multiple transition metal ions. The superior supercapacitive performance of the MnCO3 QDs/NiH–Mn–CO3 composites makes them promising cathode materials for high energy density asymmetric supercapacitors.</P></▼2>

Experimental study of vibration characteristics of FRP cables based on Long-Gauge strain

Qi Xia,JiaJia Wu,XueWu Zhu,Jian Zhang 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.63 No.6

Steel cables as the most important components are widely used in the certain types of structures such as cablesupported bridges, but the long-span structures may result in an increase in fatigue under high stress and corrosion of steel cables. The traditional steel cable is becoming a more evident hindrance. Fiber Reinforced Polymer (FRP) cables with lightweight, high-strength are widely used in civil engineering, but there is little research in vibrational characteristics of FRP cables, especially on the damping characteristic. This article studied the two methods to evaluate dynamical damping characteristic of basalt FRP(BFRP) and glass FRP(GFRP) cables. First, the vibration tests of the B/G FRP cables with different diameter and different cable force were executed. Second, the cables forces were calculated using dynamic strain, static strain and dynamic acceleration respectively, which were further compared with the measured force. Third, experimental modal damping of each cables was calculated by the half power point method, and was compared with the calculation by Rayleigh damping theory and energy dissipation damping theory. The results indicate that (1) The experimental damping of FRP cables decreases with the increase of cable force, and the trend of experimental damping changes is roughly similar with the theoretical damping. (2) The distribution of modal damping calculated by Rayleigh damping theory is closer to the experimental results, and the damping performance of GFRP cables is better than BFRP cables.

Seawater electrolyte-mediated high volumetric MXene-based electrochemical symmetric supercapacitors

Xia, Qi Xun,Shinde, Nanasaheb M.,Zhang, Tengfei,Yun, Je Moon,Zhou, Aiguo,Mane, Rajaram S.,Mathur, Sanjay,Kim, Kwang Ho The Royal Society of Chemistry 2018 Dalton Transactions Vol.47 No.26

<P>The structure and morphology of titanium carbide (Ti3C2Tx) MXene, a new class of two dimensional (2D) materials, are investigated and reported. Ti3AlC2 MAX, treated with a hydrofluoric acid etching process, is used as a promising electrode material for electrochemical supercapacitor studies. The electrochemical supercapacitor performance of Ti3C2Tx as a negatrode in a natural seawater electrolyte solution, tested in a three-electrode system, demonstrated a specific capacitance of 67.7 F g<SUP>−1</SUP> at a current density of 1 A g<SUP>−1</SUP> which is in accordance with the volumetric specific capacitance of 121.8 F cm<SUP>−3</SUP>. A symmetric supercapacitor assembled with a Ti3C2Tx//Ti3C2Tx electrode configuration revealed a volumetric specific capacitance of 27.4 F cm<SUP>−3</SUP> at 0.25 A g<SUP>−1</SUP>, and 96.6% capacitance retention even after 5000 cycles, which is superior to those reported previously in similar systems, suggesting the importance of abundant and cost-effective seawater as a natural electrolyte in developing energy storage devices.</P>

Bismuth Oxychloride/MXene symmetric supercapacitor with high volumetric energy density

Xia, Qi Xun,Shinde, Nanasaheb M.,Yun, Je Moon,Zhang, Tengfei,Mane, Rajaram S.,Mathur, Sanjay,Kim, Kwang Ho Elsevier 2018 ELECTROCHIMICA ACTA Vol.271 No.-

<P><B>Abstract</B></P> <P>Since the discovery of two-dimensional (2D) graphene, a new class of 2D materials with excellent electrical conductivity has recently been attracting attention in studying promising electrode materials in energy storage applications. Herein, bismuth oxychloride nanosheets-immobilised Ti<SUB>3</SUB>C<SUB>2</SUB>T<SUB>x</SUB> MXene material (TCBOC) is synthesised by a facile and cost-effective chemical bath deposition (CBD) route. The bismuth oxychloride (BiOCl) nanosheets are grown and immobilised on surfaces of Ti<SUB>3</SUB>C<SUB>2</SUB>T<SUB>x</SUB>-MXene flakes. An electrode based on the TCBOC nanocomposite exhibited a remarkably volumetric specific capacitance of 396.5 F cm<SUP>-3</SUP> at 1 A g<SUP>−1</SUP> and 228.0 F cm<SUP>-3</SUP> at 15 A g<SUP>−1</SUP>. Furthermore, a symmetric supercapacitor (SSC) assembled using TCBOC material proves to have a high energy density of 15.2 Wh kg<SUP>−1</SUP> at a power density of 567.4 W kg<SUP>−1</SUP> compared to SSCs using previously reported Ti<SUB>3</SUB>C<SUB>2</SUB>T<SUB>x</SUB> MXene materials. The SSC shows cycle life retention of 85.0% after 5000 cycles (at 5 A g<SUP>−1</SUP>). The enhanced capacitive performance is attributed to the increased surface area due to BiOCl nanosheets anchored on a 2D MXene surface, the activities of BiOCl sheets, and the excellent conductivity of a Ti<SUB>3</SUB>C<SUB>2</SUB>T<SUB>x</SUB> MXene material.</P>

Vibration analysis of train-bridge system with a damaged pier by flotilla collision and running safety of high-speed train

Chaoyi Xia,Kunpeng Wang,Jiacheng Huang,He Xia,Lin Qi,Xuan Wu 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.81 No.1

The dynamic responses of a pier-pile-soil system subjected to a barge/flotilla collision are analyzed. A coupled highspeed train and bridge system with a damaged pier after barge/flotilla collision is established by taking the additional unevenness of the track induced by the damaged pier as the self-excitation of the system. The whole process of a CRH2 high-speed train running on the 6×32 m simply-supported PC (prestressed concrete) box-girder bridge with a damaged pier is simulated as a case study. The results show that the lateral displacements and accelerations of the bridge with a damaged pier are much greater than the ones before the collision. The running safety indices of the train increase with the train speed as well as with the number of barges in the flotilla. In flotilla collision, the lateral wheel/rail forces of the train exceed the allowable values at a certain speed, which influences the running safety of the trains.

Dynamic analysis of coupled train - ladder track - elevated bridge system

He Xia,Yushu Deng,Chaoyi Xia,G. De Roeck,Lin Qi,Lu Sun 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.47 No.5

As a new type of vibration reduction, the ladder track system has been successfully used in engineering. In this paper, a numerical model of the train-track-viaduct system is established to study the dynamic responses of an elevated bridge with ladder track. The system is composed of a vehicle submodel, a track submodel and a bridge submodel, with the measured track irregularities as the system self-excitation. The whole time histories of a train running through an elevated bridge with 3×27m continuous PC box girders are simulated. The dynamic responses of the bridge such as deflections, lateral and vertical accelerations, and the vehicle responses such as derailment factors, offload factors and car-body accelerations are calculated. The calculated results are partly validated through the comparison with the experimental data. Compared to the common slab track, adapting the ladder sleeper can effectively reduce the accelerations of the bridge girder, and also reduce the car-body accelerations and offload factors of the train vehicle.

Function of Global Regulator CodY in Bacillus thuringiensis BMB171 by Comparative Proteomic Analysis

( Ming Xia Qi ),( Fei Mei ),( Hui Wang ),( Ming Sun ),( Ge Jiao Wang ),( Ziniu Yu ),( Yeon Ho Je ),( Ming Shun Li ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.2

CodY is a highly conserved protein in low G+C gram-positive bacteria that regulates genes involved in sporulation and stationary-phase adaptation. Bacillus thuringiensis is a grampositive bacterium that forms spores and parasporal crystals during the stationary phase. To our knowledge, the regulatory mechanism of CodY in B. thuringiensis is unknown. To study the function of CodY protein in B. thuringiensis, BMB171codY- was constructed in a BMB171 strain. A shuttle vector containing the ORF of cry1Ac10 was transformed into BMB171 and BMB171codY-, named BMB171cry1Ac and BMB171codY-cry1Ac, respectively. Some morphological and physiological changes of codY mutant BMB171codY-cry1Ac were observed. A comparative proteomic analysis was conducted for both BMB171codY-cry1Ac and BMB171cry1Ac through two-dimensional gel electrophoresis and MALDI-TOF-MS/MS analysis. The results showed that the proteins regulated by CodY are involved in microbial metabolism, including branched-chain amino acid metabolism, carbohydrate metabolism, fatty acid metabolism, and energy metabolism. Furthermore, we found CodY to be involved in sporulation, biosynthesis of poly-β-hydroxybutyrate, growth, genetic competence, and translation. According to the analysis of differentially expressed proteins, and physiological characterization of the codY mutant, we performed bacterial one-hybrid and electrophoretic mobility shift assay experiments and confirmed the direct regulation of genes by CodY, specifically those involved in metabolism of branched-chain amino acids, ribosomal recycling factor FRR, and the late competence protein ComER. Our data establish the foundation for in-depth study of the regulation of CodY in B. thuringiensis, and also offer a potential biocatalyst for functions of CodY in other bacteria.

Prognostic Perspectives of STING and PD-L1 Expression and Correlation with the Prognosis of Epstein-Barr Virus-Associated Gastric Cancers

( Qi Sun ),( Yao Fu ),( Xiaobing Chen ),( Lin Li ),( Hongyan Wu ),( Yixuan Liu ),( Haojun Xu ),( Guoren Zhou ),( Xiangshan Fan ),( Hongping Xia ) 대한소화기기능성질환·운동학회 2022 Gut and Liver Vol.16 No.6

Background/Aims: Epstein-Barr virus-associated gastric cancers (EBVaGCs) have unique molecular and clinicopathological characteristics. The cyclic GMP-AMP synthase-stimulator of interferon genes (STING) pathway is recently recognized as the critical innate immunity against pathogens and tumors. STING is also a master regulator in the cancer-immunity cycle and targeting STING could synergize with existing immune-checkpoint therapies. However, the role of STING in GC, especially in EBVaGC, and its correlation with programmed death-ligand 1 (PD-L1) remain largely unclear. Methods: We collected 78 cases of EBVaGCs and 210 cases of EBV-negative GC (EBVnGC) from a total of 1,443 cases of GC analyzed by EBV-encoded small RNA in situ hybridization. We investigated STING and PD-L1 expression and their concomitant prognostic value in EBVaGCs and EBVnGCs using tissue microarray and immunohistochemistry. The effects of STING and PD-L1 expression on the overall survival of patients with EBVaGC or EBVnGC were assessed by univariate and multivariate analysis. Results: We found that both STING and PD-L1 exhibited significantly higher expression in the EBVaGCs than that in the EBVnGCs. The expression of STING was positively correlated with that of PD-L1 in EBVaGCs. Simultaneous negative expression of STING and PD-L1, and positive expression of STING were independent prognostic risk factors for EBVaGC and EBVnGC, respectively. Conclusions: This is the first prognostic retrospective study of STING and PD-L1 expression and the prognosis among EBVaGC and EBVnGC. The expression and prognostic value of STING and PD-L1 are different in the two types of GCs. STING and PD-L1 are promising prognostic biomarkers and therapeutic targets for EBVaGC and EBVnGC. (Gut Liver 2022;16:875-891)

Carnosic acid protects against acetaminophen-induced hepatotoxicity by potentiating Nrf2-mediated antioxidant capacity in mice

Qi Guo,Zhiyang Shen,Hongxia Yu,Gaofeng Lu,Yong Yu,Xia Liu,Pengyuan Zheng 대한생리학회-대한약리학회 2016 The Korean Journal of Physiology & Pharmacology Vol.20 No.1

Acetaminophen (APAP) overdose is one of the most common causes of acute liver failure. The study aimed to investigate the protective effect of carnosic acid (CA) on APAP-induced acute hepatotoxicity and its underlying mechanism in mice. To induce hepatotoxicity, APAP solution (400 mg/kg) was administered into mice by intraperitoneal injection. Histological analysis revealed that CA treatment significantly ameliorated APAP-induced hepatic necrosis. The levels of both alanine aminotransferase (ALT) and aspartate transaminase (AST) in serum were reduced by CA treatment. Moreover, CA treatment significantly inhibited APAP-induced hepatocytes necrosis and lactate dehydrogenase (LDH) releasing. Western blot analysis showed that CA abrogated APAP-induced cleaved caspase-3, Bax and phosphorylated JNK protein expression. Further results showed that CA treatment markedly inhibited APAP-induced pro-inflammatory cytokines TNF-a, IL-1b, IL-6 and MCP-1 mRNA expression and the levels of phosphorylated IkBa and p65 protein in the liver. In addition, CA treatment reduced APAP- induced hepatic malondialdehyde (MDA) contents and reactive oxygen species (ROS) accumulation. Conversely, hepatic glutathione (GSH) level was increased by administration of CA in APAP-treated mice. Mechanistically, CA facilitated Nrf2 translocation into nuclear through blocking the interaction between Nrf2 and Keap1, which, in turn, upregulated anti-oxidant genes mRNA expression. Taken together, our results indicate that CA facilitates Nrf2 nuclear translocation, causing induction of Nrf2-dependent genes, which contributes to protection from acetaminophen hepatotoxicity.