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Wave propagation in a concrete filled steel tubular column due to transient impact load
Xuanming Ding,Yuming Fan,Gangqiang Kong,Changjie Zheng 국제구조공학회 2014 Steel and Composite Structures, An International J Vol.17 No.6
This study aims to present a three dimensional finite element model to investigate the wave propagation in a concrete filled steel tubular column (CFSC) due to transient impact load. Both the concrete and steel are regarded as linear elastic material. The impact load is simulated by a semi sinusoidal impulse. Besides the CFSC models, a concrete column (CC) model is established for comparing under the same loading condition. The propagation characteristics of the transient waves in CFSC are analyzed in detail. The results show that at the intial stage of the wave propagation, the velocity waves in CFSC are almost the same as those in CC before they arrive at the steel tube. When the waves reach the column side, the velocity responses of CFSC are different from those of CC and the difference is more and more obvious as the waves travel down along the column shaft. The travel distance of the wave front in CFSC is farther than that in CC at the same time. For different wave speeds in steel and concrete material, the wave front in CFSC presents an arch shape, the apex of which locates at the center of the column. Differently, the wave front in CC presents a plane surface. Three dimensional effects on top of CFSC are obvious, therefore, the peak value and arrival time of incident wave crests have great difference at different locations in the radial direction. High-frequency waves on the waveforms are observed. The time difference between incident and reflected wave peaks decreases significantly with r/R when r/R < 0.6, however, it almost keeps constant when r/R ≥ 0.6. The time duration between incident and reflected waves calculated by 3D FEM is approximately equal to that calculated by 1D wave theory when r/R is about 2/3.
Experimental Study of Adaptive Sliding Mode Control for Vibration of a Flexible Rectangular Plate
Jingyu Yang,Zhiqi Liu,Xuanming Cui,Shiying Qu,Chu Wang,Zhou Lanwei,Guoping Chen 한국항공우주학회 2015 International Journal of Aeronautical and Space Sc Vol.16 No.1
This paper aims to address the intelligent active vibration control problem of a flexible rectangular plate vibration involving parameter variation and external disturbance. An adaptive sliding mode (ASM) MIMO control strategy and smart piezoelectric materials are proposed as a solution, where the controller design can deal with problems of an external disturbance and parametric uncertainty in system. Compared with the current ‘classical’ control design, the proposed ASM MIMO control strategy design has two advantages. First, unlike existing classical control algorithms, where only low intelligence of the vibration control system is achieved, this paper shows that high intelligent of the vibration control system can be realized by the ASM MIMO control strategy and smart piezoelectric materials. Second, the system performance is improved due to two additional terms obtained in the active vibration control system. Detailed design principle and rigorous stability analysis are provided. Finally, experiments and simulations were used to verify the effectiveness of the proposed strategy using a hardware prototype based on NI instruments, a MATLAB/SIMULINK platform, and smart piezoelectric materials.
Experimental Study of Adaptive Sliding Mode Control for Vibration of a Flexible Rectangular Plate
Yang, Jingyu,Liu, Zhiqi,Cui, Xuanming,Qu, Shiying,Wang, Chu,Lanwei, Zhou,Chen, Guoping The Korean Society for Aeronautical and Space Scie 2015 International Journal of Aeronautical and Space Sc Vol.16 No.1
This paper aims to address the intelligent active vibration control problem of a flexible rectangular plate vibration involving parameter variation and external disturbance. An adaptive sliding mode (ASM) MIMO control strategy and smart piezoelectric materials are proposed as a solution, where the controller design can deal with problems of an external disturbance and parametric uncertainty in system. Compared with the current 'classical' control design, the proposed ASM MIMO control strategy design has two advantages. First, unlike existing classical control algorithms, where only low intelligence of the vibration control system is achieved, this paper shows that high intelligent of the vibration control system can be realized by the ASM MIMO control strategy and smart piezoelectric materials. Second, the system performance is improved due to two additional terms obtained in the active vibration control system. Detailed design principle and rigorous stability analysis are provided. Finally, experiments and simulations were used to verify the effectiveness of the proposed strategy using a hardware prototype based on NI instruments, a MATLAB/SIMULINK platform, and smart piezoelectric materials.
CD160 is essential for NK-mediated IFN-γ production
Tu, Tony C.,Brown, Nicholas K.,Kim, Tae-Jin,Wroblewska, Joanna,Yang, Xuanming,Guo, Xiaohuan,Lee, Seoyun Hyunji,Kumar, Vinay,Lee, Kyung-Mi,Fu, Yang-Xin The Rockefeller University Press 2015 The Journal of experimental medicine Vol.212 No.3
<P>NK-derived cytokines play important roles for natural killer (NK) function, but how the cytokines are regulated is poorly understood. CD160 is expressed on activated NK or T cells in humans but its function is unknown. We generated CD160-deficient mice to probe its function. Although CD160<SUP>−/−</SUP> mice showed no abnormalities in lymphocyte development, the control of NK-sensitive tumors was severely compromised in CD160<SUP>−/−</SUP> mice. Surprisingly, the cytotoxicity of NK cells was not impaired, but interferon-γ (IFN-γ) secretion by NK cells was markedly reduced in CD160<SUP>−/−</SUP> mice. Functionally targeting CD160 signaling with a soluble CD160-Ig also impaired tumor control and IFN-γ production, suggesting an active role of CD160 signaling. Using reciprocal bone marrow transfer and cell culture, we have identified the intrinsic role of CD160 on NK cells, as well as its receptor on non-NK cells, for regulating cytokine production. To demonstrate sufficiency of the CD160<SUP>+</SUP> NK cell subset in controlling NK-dependent tumor growth, intratumoral transfer of the CD160<SUP>+</SUP> NK fraction led to tumor regression in CD160<SUP>−/−</SUP> tumor-bearing mice, indicating demonstrable therapeutic potential for controlling early tumors. Therefore, CD160 is not only an important biomarker but also functionally controls cytokine production by NK cells.</P>
Research Progress of the Structure Vibration-Attitude Coordinated Control of Spacecraft
Yang, Jingyu,Qu, Shiying,Lin, Jiahui,Liu, Zhiqi,Cui, Xuanming,Wang, Chu,Zhang, Dujiang,gu, Mingcheng,Sun, Zhongrui,Yang, Kang,Zhou, Lanwei,Chen, Guoping The Korean Society for Aeronautical and Space Scie 2015 International Journal of Aeronautical and Space Sc Vol.16 No.4
This paper gives an overview of research on the field of structure vibration-attitude coordinated control of spacecraft. First of all, the importance of the technology has been given an introduction, and then later the research progress of space structure dynamics modeling, research progress of structure vibration-attitude coordinated control of flexible spacecraft have been discussed respectively. Finally, future research on application of structure vibration-attitude coordinated control of spacecraft has been recommended.
Keqin Deng,Qiming Wang,Jianxin Zeng,Xinhong Guo,Xiaoying Zhao,Dongying Tang,Xuanming Liu 한국식물학회 2009 Journal of Plant Biology Vol.52 No.6
Lectin receptor-like kinases (LecRK) are widespread in higher plants; however, little is known about their physiological roles. In this study, At1g70130 (designated LecRK-b2), an Arabidopsis LecRK gene, has been investigated. LecRK-b2 was predominantly expressed during seed germination, and its expression was ceased following germination. The expression of LecRK-b2 was induced by abscisic acid (ABA), salt, and osmotic stress. LecRK-b2 lossof- function mutation slightly reduced the ABA sensitivity during seed germination, and this reduced sensitivity was demonstrated not due to lower ABA accumulation level in the seeds. Dual-luciferase transient expression assay confirmed that the transcription factor ABSCISIC ACID INSENSITIVE3 (ABI3) could activate the luciferase under driving of LecRK-b2 promoter. LecRK-b2 transcription level was found to be down-regulated in abi3 during seed germination. Furthermore, LecRK-b2 loss-of-function mutation reduced the salt and osmotic sensitivity during early development stage of Arabidopsis. Taken together, these results suggest that LecRK-b2 functions as a positive regulator of the ABA response during the seed germination and is involved in salt and osmotic stress response in the early development stage.
Qiming Wang,Xiaoju Tu,Keqin Deng,Jianxin Zeng,Xiaoying Zhao,Dongying Tang,Xuanming Liu 한국식물학회 2009 Journal of Plant Biology Vol.52 No.6
The double B-box (DBB) type zinc finger protein has thus far been shown to be involved in photomorphegenesis in Arabidopsis thaliana. Here, we show that DBB1a is expressed in the embryo, cytolden, and flower. Misexpression of DBB1a in mutant plants resulted in abnormal numbers and patterns of floral organs. We further show that DBB1a could regulate expression of several floral homeotic genes, including APETALA 2, APETALA 3, PISTILLATA, and AGAMOUS. Interestingly, expression of the microRNA gene MiR172, which is involved in organ boundary establishment, was also misregulated in the dbb1a mutant plants. Our study identified a previously uncharacterized role of DDB1a in regulation of expression of floral homeotic genes and miR172, which is important for understanding of floral pattern formation.
Research Progress of the Structure Vibration-Attitude Coordinated Control of Spacecraft
Jingyu Yang,Shiying Qu,Jiahui Lin,Zhiqi Liu,Xuanming Cui,Chu Wang,Dujiang Zhang,Mingcheng gu,Zhongrui Sun,Kang Yang,Lanwei Zhou,Guoping Chen 한국항공우주학회 2015 International Journal of Aeronautical and Space Sc Vol.16 No.4
This paper gives an overview of research on the field of structure vibration-attitude coordinated control of spacecraft. First of all, the importance of the technology has been given an introduction, and then later the research progress of space structure dynamics modeling, research progress of structure vibration-attitude coordinated control of flexible spacecraft have been discussed respectively. Finally, future research on application of structure vibration-attitude coordinated control of spacecraft has been recommended.
Bo Zhou,Dan Peng,Jianzhong Lin,Xingqun Huang,Wusheng Peng,Reqing He,Ming Guo,Dongying Tang,Xiaoying Zhao,Xuanming Liu 한국식물학회 2011 Journal of Plant Biology Vol.54 No.1
Gibberellins (GAs) are endogenous hormones that play an important role in regulating plant stature by increasing cell division and promoting seed germination. The GA2-oxidase gene from Arabidopsis thaliana (AtGA2ox8) was introduced into Brassica napus L. by Agrobacterium-mediated floral-dip transformation with the aim of decreasing the amount of bioactive GA and hence reduced the plant height. As anticipated, the transgenic plant exhibited dwarf phenotype. Importantly, compared with the wild type, the transgenic plants had delayed the seed germination, increased the chlorophyll content (28.7–36.3%) and photosynthesis capacity (14.3–18.7%) in a single leaf. At the same time, the photosynthesis capacity of the whole plants was significantly enhanced (35.7–48.6%) due to the extra leaves and branches.