Random vibration analysis of train-slab track-bridge coupling system under earthquakes

Zhi-ping Zeng,Xian-feng He,Yan-gang Zhao,Zhi-wu Yu,Ling-kun Chen,Wen-tao Xu,Ping Lou 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.54 No.5

This study aimed to investigate the random vibration characteristic of train-slab track-bridge interaction system subjected to both track irregularities and earthquakes by use of pseudo-excitation method (PEM). Each vehicle subsystem was modeled by multibody dynamics. A three-dimensional rail-slabgirder-pier finite element model was created to simulate slab track and bridge subsystem. The equations of motion for the entire system were established based on the constraint condition of no jump between wheel and rail. The random load vectors of equations of motion were formulated by transforming track irregularities and seismic accelerations into a series of deterministic pseudo-excitations according to their respective power spectral density (PSD) functions by means of PEM. The time-dependent PSDs of random vibration responses of the system were obtained by step-by-step integration method, and the corresponding extreme values were estimated based on the first-passage failure criterion. As a case study, an ICE3 high-speed train passing a fifteen-span simply supported girder bridge simultaneously excited by track irregularities and earthquakes is presented. The evaluated extreme values and the PSD characteristic of the random vibration responses of bridge and train are analyzed, and the influences of train speed and track irregularities (without earthquakes) on the random vibration characteristic of bridge and train are discussed.

Correlation between rearing temperature and the dual cellulolytic system of Coptotermes formosanus Shiraki and its intestinal microenvironment

Wen-Hui Zeng,Zhi-Qiang Li,Bing-Rong Liu,Qiu-Jian Li,Jun-Hong Zhong 한국응용곤충학회 2016 Journal of Asia-Pacific Entomology Vol.19 No.1

The lower termite, Coptotermes formosanus Shiraki, is an important model species for studying the dual cellulolytic system of termites. The effect of rearing temperature on the interaction between the intestinal symbiont community and the host in lignocelluloses digestion was investigated by assaying the activity and gene expression of cellulase, and monitoring the population size of intestinal protozoan community, which was followed by rearing C. formosanus at a temperature gradient (15–37 °C) for 3 d. The results showed that the rearing temperature of C. formosanus had a much greater impact on cellulase activity and gene transcription of the intestinal symbiont than on the host. The transcriptional variations of endogenous and symbiotic cellulase genes presented mutual complement and restrained when C. formosanus living in high temperature environment (32 and 37 °C). Additionally, the optimum survival temperature of Pseudotrichonympha grassii Koidzumi (22 °C) was found lower than that of Holomastigotoides mirabile Koidzumi (28 °C) and Spirotrichonympha leidyi Koidzumi (28 °C).The optimum rearing temperature for cellulase activity and protozoan survival of C. formosanus was found much lower than its optimum temperature for feeding. These findings provide a novel glimpse into host-symbiotic mutualism in lower termite digestion.

Preliminary Studies on Species of Edible Spiders in Folk China

Wang Zhi,Li Wen-Jian,Zeng Bai-Ping,Yan Heng-Mei,Joo-Pil Kim 한국거미연구소 2001 한국거미 Vol.17 No.2

Comparative field tests on uplift behavior of straight-sided and belled shafts in loess under an arid environment

Qian, Zeng-zhen,Lu, Xian-long,Yang, Wen-zhi,Cui, Qiang Techno-Press 2016 Geomechanics & engineering Vol.11 No.1

This study elucidates the uplift behaviors of the straight-sided and belled shafts. The field uplift load tests were carried out on 18 straight-sided and 15 belled shafts at the three collapsible loess sites under an arid environment on the Loess Plateau in Northwest China. Both the site conditions and the load tests were documented comprehensively. In general, the uplift load-displacement curves of the straight-sided and belled shafts approximately exhibited an initial linear, a curvilinear transition, and a final linear region, but did not provide a well defined peak or asymptotic value of the load, and therefore their uplift resistances should be interpreted from the load test results using an appropriate criterion. Nine representative uplift resistance interpretation criteria were used to define the "interpreted failure load" for each of the load tests, and all of these interpreted uplift resistances were normalized by the failure threshold, $T_{L2}$, obtained using the $L_1-L_2$ method. These load test data were compared statistically and graphically. For the straight-sided and belled shafts, the normalized uplift load-displacement curves were respectively established by the plots that related the mean interpreted uplift resistance ratio against the mean displacement at the corresponding interpreted criteria, and the comparisons of the normalized load-displacement curves were made. Specific recommendations for the designs of uplift belled and straight-sided shafts in the loess were given, in terms of both capacity and displacement.

Behaviour of micropiles in collapsible loess under tension or compression load

Qian, Zeng-Zhen,Lu, Xian-Long,Yang, Wen-Zhi,Cui, Qiang Techno-Press 2014 Geomechanics & engineering Vol.7 No.5

This study examines the behaviour of single micropiles subjected to axial tension or compression load in collapsible loess under in-situ moisture content and saturated condition. Five tension loading tests and five compression loading tests on single micropiles were carried out at a typical loess site of the Loess Plateau in Northwest China. A series of laboratory tests, including grain size distribution, specific gravity, moisture content, Atterberg limits, density, granular components, shear strength, and collapse index, were carried out during the micropile loading tests to determine the values of soil parameters. The loess at the test site poses a severe collapse risk upon wetting. The tension or compression load-displacement curves of the micropiles in loess, under in-situ moisture content or saturated condition, can generally be simplified into three distinct regions: an initial linear, a curvilinear transition, and a final linear region, and the bearing capacity or failure load can be interpreted by the L1-L2 method as done in other studies. Micropiles in loess should be considered as frictional pile foundations though the tip resistances are about 10%-15% of the applied loads. Both the tension and compression capacities increase linearly with the ratio of the pile length to the shaft diameter, L/d. For micropiles in loess under in-situ moisture content, the interpreted failure loads or capacities under tension are 66%-87% of those under compression. However, the prewetting of the loess can lead to the reductions of 50% in the tensile bearing capacity and 70% in the compressive bearing capacity.

Study on the Effect of Temperature and Illumination on Omithoctonus huwena's Predation

Wang Zhi,Zeng Bo-Ping,Li Wen-Jian,Wang Wen-Bin,Yan Heng-Mei,Joo-Pil Kim 한국거미연구소 2001 한국거미 Vol.17 No.2

Two new sesquiterpenoids from endophytic fungus J3 isolated from Mangrove Plant Ceriops tagal

Yan-Bo Zeng,Hai-Gang Gu,Wen-Jian Zuo,Li-Li Zhang,Hong-Jin Bai,Zhi-Kai Guo,Peter Proksch,Wen Li Mei,Hao Fu Dai 대한약학회 2015 Archives of Pharmacal Research Vol.38 No.5

Two new sesquiterpenoids, named 2a-hydroxyxylaranolB (1) and 4b-hydroxyxylaranol B (2), togetherwith a known diterpenoid 3,4-seco-sonderianol (3) wereisolated from the fermentation of endophytic fungus J3 ofCeriops tagal. Their structures were elucidated based onspectroscopic methods including 1D and 2D NMR(HMQC, 1H-1H COSY and HMBC). All compounds wereevaluated for their cytotoxic activities by MTT method,and compound 3 exhibited cytotoxic activities againstK562, SGC-7901, and BEL-7402 cell lines.

Protective effects of l-theanine on rats with dextran sulfate sodium-induced infl ammatory bowel disease

Ling Chen,Wen-jun Xiao,Qiong-xian Yan,Zhi-hua Gong,Sheng Zhang,Li Zeng,Ming Yang,Yan-he Zhou 대한약학회 2020 Archives of Pharmacal Research Vol.43 No.8

The aim of this study is to evaluate the antiinflammatory and protective eff ects of L -theanine in infl ammatorybowel disease (IBD) and to identify the underlyingmolecular mechanisms. Rats were pre-treated with L -theanineat 0, 50, 200, or 800 mg/kg/day. IBD was induced inrats using dextran sulfate sodium (DSS). Histopathologicalanalysis suggests that L -theanine can suppress DSS-inducedIBD with signifi cant inhibition of infl ammation in large andsmall intestinal tissues. Moreover, the 200 mg/kg/day L -theanine-treated DSS group had higher body and small intestineweights, a lower disease activity index and expression ofinfl ammatory factors than the DSS group without pre-treatment. In RNA sequencing and tandem mass tag labelinganalyses, large number of mRNAs and proteins expressionlevel diff ered when compared with the DSS-induced ratswith and without 200 mg/kg/day L -theanine pre-treatment. Moreover, Kyoto Encyclopedia of Genes and Genomes pathwayanalysis indicates the anti-infl ammatory activities ofL -theanine in DSS-induced IBD, with a high representationof genes in “Cholesterol metabolism” and “Retinol metabolism”pathways. Analysis of protein–protein interaction networksfurther indicates the involvement of these two pathways. These studies suggest that medium-dose L -theaninepre-treatment could ameliorate DSS-induced IBD throughmolecular mechanisms involving cholesterol and retinolmetabolism.

Characterization and uncertainty of uplift load-displacement behaviour of belled piers

Lu, Xian-long,Qian, Zeng-zhen,Zheng, Wei-feng,Yang, Wen-zhi Techno-Press 2016 Geomechanics & engineering Vol.11 No.2

A total of 99 full-scale field load tests at 22 sites were compiled for this study to elucidate several issues related to the load-displacement behaviour of belled piers under axial uplift loading, including (1) interpretation criteria to define various elastic, inelastic, and "failure" states for each load test from the load-displacement curve; (2) generalized correlations among these states and determinations to the predicted ultimate uplift resistances; (3) uncertainty in the resistance model factor statistics required for reliability-based ultimate limit state (ULS) design; (4) uncertainty associated with the normalized load-displacement curves and the resulting model factor statistics required for reliability-based serviceability limit state (SLS) design; and (5) variations of the combined ULS and SLS model factor statistics for reliability-based limit state designs. The approaches discussed in this study are practical and grounded realistically on the load tests of belled piers with minimal assumptions. The results on the characterization and uncertainty of uplift load-displacement behaviour of belled piers could be served as to extend the early contributions for reliability-based ULS and SLS designs.

Mortality Characteristic and Prediction of Nasopharyngeal Carcinoma in China from 1991 to 2013

Xu, Zhen-Xi,Lin, Zhi-Xiong,Fang, Jia-Ying,Wu, Ku-Sheng,Du, Pei-Ling,Zeng, Yang,Tang, Wen-Rui,Xu, Xiao-Ling,Lin, Kun Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.15

Background: To analyze the mortality distribution of nasopharyngeal carcinoma in China from 1991 to 2013, to predict the mortality in the ensuing five years, and to provide evidence for prevention and treatment of nasopharyngeal carcinoma. Materials and Methods: Mortality data for Nasopharyngeal Carcinoma in China from 1991 to 2013 were used to describe its epidemiological characteristics, such as the change of the standardized mortality rate, sex and age differences, urban-rural differences. Trend-surface analysis was used to study the geographical distribution of the mortality. Curve estimation, time series, gray modeling, and joinpoint regression were used to predict the mortality for the ensuing five years in the future. Results: In China, the standardized mortality rate of Nasopharyngeal Carcinoma increased with time from 1996, reaching the peak values of $1.45/10^5$ at the year of 2002, and decreased gradually afterwards. With males being 1.51 times higher than females, and the city had a higher rate than the rural during the past two decades. The mortality rate increased from age 40. Geographical analysis showed the mortality rate increased from middle to southern China. Conclusions: The standardized mortality rate of Nasopharyngeal Carcinoma is falling. The regional disease control for Nasopharyngeal Carcinoma should be focused on Guangdong province of China, and the key targets for prevention and treatment are rural men, especially after the age of 40. The mortality of Nasopharyngeal Carcinoma will decrease in the next five years.