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RISS 인기검색어
- 검색키워드
- 저자 : Xiangguo Liu (검색결과 5 건)
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Cracks evolution and multifractal of acoustic emission energy during coal loading
Kong, Xiangguo,Wang, Enyuan,He, Xueqiu,Liu, Xiaofei,Li, Dexing,Liu, Quanlin Techno-Press 2018 Geomechanics & engineering Vol.14 No.2
Coal samples with different joints morphology were subjected to uniaxial compression experiments, cracks evolution was recorded by Nikon D5300 and acoustic emission (AE) energy signals were collected by AEwin Test for Express-8.0. During loading process, coal samples deformed elastically with no obvious cracks changes, then they expanded gradually along the trace of the original cracks, accompanied by the formation of secondary cracks, and eventually produced a large-scale fracture. It was more interesting that the failure mode of samples were all shear shape, whatever the original cracks morphology was. With cracks and damage evolution, AE energy radiated regularly. At the early loading stage, micro damage and small scale fracture events only induced a few AE events with less energy, while large scale fracture leaded to a number of AE events with more energy at the later stage. Based on the multifractal theory, the multifractal spectrum could explain AE energy signals frequency responses and the causes of AE events with load. Multifractal spectrum width (${\Delta}{\alpha}$), could reflect the differences between the large and small AE energy signals. And another parameter (${\Delta}f$) could reflect the relationship between the frequency of the least and greatest signals in the AE energy time series. This research is helpful for us to understand cracks evolution and AE energy signals causes.
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Behavior of UHPC-RW-RC wall panel under various temperature and humidity conditions
Wu, Xiangguo,Yu, Shiyuan,Tao, Xiaokun,Chen, Baochun,Liu, Hui,Yang, Ming,Kang, Thomas H.K. Techno-Press 2020 Advances in concrete construction Vol.9 No.5
Mechanical and thermal properties of composite sandwich wall panels are affected by changes in their external environment. Humidity and temperature changes induce stress on wall panels and their core connectors. Under the action of ambient temperature, temperature on the outer layer of the wall panel changes greatly, while that on the inner layer only changes slightly. As a result, stress concentration exists at the intersection of the connector and the wall blade. In this paper, temperature field and stress field distribution of UHPC-RW-RC (Ultra-High Performance Concrete - Rock Wool - Reinforced Concrete) wall panel under high temperature-sprinkling and heating-freezing conditions were investigated by using the general finite element software ABAQUS. Additionally, design of the connection between the wall panel and the main structure is proposed. Findings may serve as a scientific reference for design of high performance composite sandwich wall panels.
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Wenlu Guo,Xiangguo Meng,Yan Liu,Liang Ni,Zhaoyong Hu,Rui Chen,Minjia Meng,Yun Wang,Juan Han,Min Luo 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1
The new 8-hydroxyquinoline (8-HQ) modified magnetic mesoporous carbon (8-HQ-Ni-CMK-3) wasprepared and applied for adsorption of multivariate metal ions from aqueous solution. The preparedadsorbent was characterized by Fourier transform infrared, X-ray diffraction, scanning electronmicroscopy, transmission electron microscope, nitrogen adsorption-desorption isotherm, elementalanalysis, and vibrating sample magnetometer. The static adsorption behaviors toward multivariatemetal ions on graphite, the modified graphite by 8-HQ, magnetic mesoporous carbon, and 8-HQ-Ni-CMK-3 were compared, which showed that 8-HQ-Ni-CMK-3 had excellent adsorption capacity. Theremoval of multivariate metal ions using 8-HQ-Ni-CMK-3 by fixed-bed column was further investigated.
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Yang Zhao,Zhi Liu,Fengying Duan,Xia An,Xiangguo Liu,Dongyun Hao,Riliang Gu,Zhangkui Wang,Fanjun Chen,Lixing Yuan 한국식물생명공학회 2018 Plant biotechnology reports Vol.12 No.1
High-affinity ammonium uptake in maize roots is mainly mediated by AMT1-type ammonium transporters ZmAMT1;1a and ZmAMT1;3, but whether the increased expression of ZmAMTs genes is able to enhance ammonium uptake capacity and subsequently improves overall nitrogen use efficiency remains to be elucidated. In this work, ZmAMT1;1a-overexpression transgenic maize plants were generated with the elevated levels of transcripts and proteins, and phenotypically analyzed together with wild-type plants grown in nutrient solution under two regimes of ammonium supply. Under low ammonium nutrition (0.04 mM), in relative to wild-type plants, the maize transgenic lines showed an approximately 17% increases in the high-affinity ammonium uptake capacity of roots as revealed by 15N-labeled ammonium influx assay and further contributed to about 7% increases in the total nitrogen uptake at the whole plant level. By contrast, when ammonium was supplied in high amounts (1 mM), wild-type plants expressed higher levels of ZmAMT1;1a, but exhibited a lower ammonium uptake capacity in roots. Furthermore, the transgenic maize line accumulated more amounts of ZmAMT1;1a protein, but did not translate into an enhanced ammonium acquisition, suggesting a possible post-translational down-regulation of ZmAMT1;1a by high ammonium. This study proved the possibility to enhance ammonium acquisition by elevating ZmAMTs expression in maize roots and provided an effective transgenic approach on developing high nitrogen use efficient maize cultivars.
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Xiang Guo,Xing Wu,Xiaoqin Liu,Linjiang Tang 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.1
Using microphone array to detect the fault of rotating machinery is an effective method. Compared with the fault diagnosis based on vibration analysis, the advantage of this method is that it does not need the direct contact between the sensor and the machine. In addition, acoustic location can be realized by using microphone array, to accurately identify the sound radiation source on the machine surface. Conventional beamforming (CBF) is widely applied in noise source identification because of its fast speed. In the local reverberation environment, the conventional beamforming is disturbed by the image source, causing inaccurate judgment of the fault location and low imaging resolution. In this paper, an acoustic imaging method of averaged generalized inverse beamforming (AGIB) is proposed. Compared with CBF, generalized inverse beamforming (GIB) possess higher location accuracy. First, the spectral kurtosis (SK) can enhance the impact characteristics of fault signals. According to the center frequency and bandwidth estimated by the spectral kurtosis diagram, the impact information which adopt in beamforming location can be extracted in time domain and frequency domain by spectral kurtosis matched filter. Then the average amplitude and standard deviation of generalized inverse beamforming output at different positions are calculated. Finally, the normalized standard deviation is used for the beamforming output weighting of the central measurement position, so as to enhance the spatially invariant source contribution and effectively attenuate the ghost caused by the local reverberation environment. Through defect location of low-speed large bearing, compared with the averaged conventional beamforming (ACBF), AGIB can not only overcome the influence of local reverberation environment and accurately locate the fault location, but also improve the resolution significantly.
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