Free Vibration of the Cracked Non-uniform Beam with Cross Section Varying as Polynomial Functions

Guo-jin Tan,Yang Liu,Yafeng Gong,Yangfan Shen,Ziyu Liu 대한토목학회 2018 KSCE Journal of Civil Engineering Vol.22 No.11

This paper presents an approach for free vibration analysis of the cracked non-uniform beam with general boundary conditions, whose mass per unit length and bending moment of inertia varying as polynomial functions. Firstly, the general expression of mode shape function of the non-uniform beam with four undetermined coefficients is solved by a generalized power series method based on the Euler-Bernoulli beam theory. Then, the transfer matrix method is combined into the mode shape function of the non-uniform beam to improve the computational efficiency owe to the fewer segments divided by the cracks and joints at the different forms of variable cross-section. The massless rotational springs are adopted to simulate the cracks to derive the transfer relationship of the undetermined coefficients in the same segment. The four undetermined coefficients matrix is obtained by using equilibrium and continuity conditions between two adjacent segments, and then the characteristic equation of the entire cracked beam is formed. Finally, the correctness and reliability of the proposed method in this paper is verified by the methods presented by other published papers and the Finite Element Method (FEM). In addition, the crack parameters on the vibratory characteristics are investigated through the numerical examples.

Theoretical research on the identification method of bridge dynamic parameters using free decay response

Tan, Guo-Jin,Cheng, Yong-Chun,Liu, Han-Bing,Wang, Long-Lin Techno-Press 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.38 No.3

Input excitation and output response of structure are needed in conventional modal analysis methods. However, input excitation is often difficult to be obtained in the dynamic load test of bridge structures. Therefore, what attracts engineers' attention is how to get dynamic parameters from the output response. In this paper, a structural experimental modal analysis method is introduced, which can be used to conveniently obtain dynamic parameters of the structure from the free decay response. With known damping coefficients, this analysis method can be used to identify the natural frequencies and the mode shapes of MDOF structures. Based on the modal analysis theory, the mathematical relationship of damping ratio and frequency is obtained. By using this mathematical relationship to improve the previous method, an improved experimental modal analysis method is proposed in this paper. This improved method can overcome the deficiencies of the previous method, which can not identify damping ratios and requires damping coefficients in advance. Additionally, this improved method can also identify the natural frequencies, mode shapes and damping ratios of the bridge only from the free decay response, and ensure the stability of identification process by using modern mathematical means. Finally, the feasibility and effectiveness of this method are demonstrated by a numerical example of a simply supported reinforced concrete beam.

Free vibration analysis of continuous bridge under the vehicles

Guo-jin Tan,Wensheng Wang,Yubo Jiao,Zhigang Wei 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.61 No.3

Free vibration analysis for continuous bridge under any number of vehicles is conducted in this paper. Calculation strategy for natural frequency and mode shape is proposed based on Euler-Bernoulli beam theory and numerical assembly method. Firstly, a half-car planar model is adopted; equations of motion and displacement functions for bridge and vehicle are established, respectively. Secondly, the undermined coefficient matrices for wheels, vehicles, intermediate support, left-end support and right-end support are derived. Then, the numerical assembly technique for conventional finite element method is adopted to construct the overall matrix of coefficients for whole system. Finally, natural frequencies and corresponding mode shapes are determined based on iterative method and overall matrix solution. Numerical simulation is presented to verify the effectiveness of the proposed method. The results reveal that the solutions of present method are exact ones. Natural frequencies and associate modal shapes of continuous bridge under different conditions of vehicles are investigated. The influences of vehicle parameters on natural frequencies are also demonstrated.

Theoretical research on the identification method of bridge dynamic parameters using free decay response

Guo-jin Tan,Yong-chun Cheng,Han-bing Liu,Long-lin Wang 국제구조공학회 2011 Structural Engineering and Mechanics, An Int'l Jou Vol.38 No.3

Input excitation and output response of structure are needed in conventional modal analysis methods. However, input excitation is often difficult to be obtained in the dynamic load test of bridge structures. Therefore, what attracts engineers’ attention is how to get dynamic parameters from the output response. In this paper, a structural experimental modal analysis method is introduced, which can be used to conveniently obtain dynamic parameters of the structure from the free decay response. With known damping coefficients, this analysis method can be used to identify the natural frequencies and the mode shapes of MDOF structures. Based on the modal analysis theory, the mathematical relationship of damping ratio and frequency is obtained. By using this mathematical relationship to improve the previous method, an improved experimental modal analysis method is proposed in this paper. This improved method can overcome the deficiencies of the previous method, which can not identify damping ratios and requires damping coefficients in advance. Additionally, this improved method can also identify the natural frequencies, mode shapes and damping ratios of the bridge only from the free decay response, and ensure the stability of identification process by using modern mathematical means. Finally, the feasibility and effectiveness of this method are demonstrated by a numerical example of a simply supported reinforced concrete beam.

THE ROLE OF CONFUCIAN VALUES IN EAST ASIAN DEVELOPMENT : BEFORE AND AFTER THE FINANCIAL CRISIS

Wang, Jin-guo,Russell Smyth,Hwee, Tan-Dai 서울대학교 국제지역원 2000 Journal of International and Area Studies Vol.7 No.1

Asian Values provided a convincing cultural explanation for high economic growth in East Asia up until the recent economic crisis, without many of the social problems that are normally associated with rapid development, However, the Asian economic crisis has prompted a re-examination of Asian values. This paper argues that the positive aspects of Confucian values outweigh its minuses and that it is up to the East Asian economies to take steps to maximize its positive aspects, The paper also argues that its minuses and that it is up East Asian economies to take steps to maximize its positive aspects, The paper also argues that its Weakness cannot be entirely blamed for the Asian economic crisis and that given the overwhelming evidence of East Asia's remarkable economic performance over a sustained period, the effects of Confucianism on economic development should not be overlooked.

EFFECT OF THE STRUCTURE OF ISOMERS OF MERCAPTOVALERIC ACID ON OPTICAL PROPERTIES OF CdTe QUANTUM DOTS

KAI-GUO MA,JIN-YI BAI,TAN FANG,Haiqing Guo 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2013 NANO Vol.8 No.5

4-Mercaptovaleric acid (4MVA) and 3-mercaptovaleric acid (3MVA), two branched isomers of 5-mercaptovaleric acid (MVA), were designed and synthesized. They were used as capping agents in the aqueous synthesis of CdTe quantum dots (QDs) by a modified hydrothermal method with sodium tellurite as Te source. Compared with MVA-CdTe, either 4MVA-QDs or 3MVA-QDs exhibited higher fluorescent quantum yield (QY) and sharper absorption peak, which confirmed the superiority of using branched mercapto acids in the aqueous synthesis of QDs for improved optical properties. The fluorescence of QDs capped with 4MVA was higher than that of QDs capped with 4-mercaptobutyric acid (MBA) but lower than that of QDs capped with 3-mercaptobutyric acid (3MBA), which further confirmed the advantage of designing methyl side group rather than methylene group in the main chain for desired optical properties. However, the lower fluorescence, less sharp absorption peak and faster growth rate of 3MVA-QDs than that of 3MBA-QDs indicated adverse effect of side group on the aqueous synthesis of QDs if the size of side group is very bulky. Our results are helpful for selecting and designing appropriate capping agents for QDs with excellent properties.

Molecular identification and the role of adipokinetic hormone receptor in Helicoverpa armigera (Hübner)

Xiao Zhengkun,Jin Ruoheng,Yun Tan,Tang Jun,Huang Guo-Hua 한국응용곤충학회 2023 Journal of Asia-Pacific Entomology Vol.26 No.2

In insects, lipids and trehalose are the primary energy reserves and sources, and their metabolism is controlled by a variety of physiological processes. Adipokinetic hormone receptor (AKHR) has been reported to be involved in glycolipid metabolism and immune response, however, is an uncharted territory in Helicoverpa armigera. In the present study, the full-length cDNA encoding AKHR was isolated from H. armigera. The HaAKHR contains a seven-transmembrane domain, which was a characteristic of G-protein coupled receptors. The expression profile analysis revealed that HaAKHR was highly expressed in fat body of newly emerged female adults and highly expressed in the immature stage. The content of triglyceride (TAG) in fat body increased significantly after silencing of HaAKHR, however, the trehalase activity and the expression of trehalose-6-phosphate synthase (TPS) were decreased in hemolymph. Furthermore, the expression level of HaAKHR was significantly upregulated when infected with different kinds of entomopathogenic microbes. The above results suggested that HaAKHR plays an important role in regulating glycolipid metabolism and immune response in H. armigera, and contribute to understanding the underlying mechanism of host-pathogen interactions in H. armigera.

Reference gene selection for transcriptional profiling by RT-qPCR in the 28-spotted larger potato ladybird

Zhang Yu-Xing,Tan Qiao,Shen Chen-Hui,Wu Jian-Jian,Wu Yi-Kuan,Li Wen-Ze,Jin Lin,Li Guo-Qing 한국응용곤충학회 2022 Journal of Asia-Pacific Entomology Vol.25 No.2

Henosepilachna vigintioctomaculata is one of the most serious defoliates attacking potatoes. However, studies on functional genes have greatly been limited due to the insufficiency of effective and stable endogenous references to normalize RT-qPCR data. In this report, nine housekeeping genes (RPL4, RPL6, RPL13, RPL32, RPS18, ACT, EF1α, GAPDH and α-TUB) involved in different biological processes were selected. Their expression levels under diverse experimental conditions including developmental stages, tissues, temperatures and host plants were determined using RT-qPCR technology. The tested candidate genes were comprehensively ranked based on five alternative stability analysis methods (Ct value, geNorm, NormFinder, BestKeeper and ReFinder). The results revealed that the optimal internal reference genes varied under different experimental conditions. Any gene pair among the five candidates (RPL4, RPL13, RPL32, RPS18 and EF1α) was a suitable reference gene set under different temperatures and on different host plants. A combination of RPL6 and RPL13 was recommended as the best reference gene set across different developmental stages. A pair of RPS18 and EF1α was ranked as the optimal reference gene combination within different tissues. The most suitable reference genes were RPS18 and RPL13 under four different experimental conditions. Our findings not only establish an accurate and reliable normalization of RT-qPCR data, but also lay a solid foundation for further functional gene researches in H. vigintioctomaculata

sanN encoding a Dehydrogenase is Essential for Nikkomycin Biosynthesis in Streptomyces ansochromogenes

( Hong Bo Ling ),( Guo Jun Wang ),( Jin E Li ),( Hua Rong Tan ) 한국미생물 · 생명공학회 2008 Journal of microbiology and biotechnology Vol.18 No.3

ORiginal Article : miR-197 Expression in Peripheral Blood Mononuclear Cells from Hepatitis B Virus-Infected Patients

( Li Chen ),( Cong Zhi Li ),( Zaiquan Peng ),( Jin Xiang Zhao ),( Guo Zhong Gong ),( De Ming Tan ) The Editorial Office of Gut and Liver 2013 Gut and Liver Vol.7 No.3

Background/Aims: This study aimed to investigate the microRNA (miRNA) expression profiles in peripheral blood mononuclear cell (PBMC) of hepatitis B virus (HBV)-infected patients with different clinical manifestations and to analyze the function of miR-197. Methods: PBMC miRNA expression profiles in 51 healthy controls, 70 chronic asymptomatic carriers, 107 chronic hepatitis B patients, and 76 HBV-related acute on chronic liver failure patients were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). miR-197 mimic and inhibitor were transfected in THP-1 cells. qRT PCR and ELISA for interleukin (IL)-18 mRNA and protein levels were performed, respectively. Results: The microarray analysis revealed that 17 PBMC miRNA expression profiles (12 miRNAs downregulated and five miRNAs upregulated) differed significantly in HBV-induced liver disease patients presenting with various symptoms. The qRT-PCR results suggested that the PBMC miR-197 levels regularly decreased as the severity of liver disease symptoms became aggravated. IL 18, a key regulator in inflammation and immunity, was inversely correlated with miR-197 levels. Bioinformatic analysis indicated that IL-18 was a target of miR-197. Exogenous expression of miR-197 could significantly repress IL 18 expression at both the mRNA and protein levels in THP-1 cells. Conclusions: We concluded that multiple PBMC miRNAs had differential expression profiles during HBV infection and that miR-197 may play an important role in the reactivation of liver inflammation by targeting IL-18. (Gut Liver 2013; 7:335-342)