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Obliquely incident earthquake for soil-structure interaction in layered half space

  • Zhao, Mi;Gao, Zhidong;Wang, Litao;Du, Xiuli;Huang, Jingqi;Li, Yang
    • Earthquakes and Structures
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    • v.13 no.6
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    • pp.573-588
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    • 2017
  • The earthquake input is required when the soil-structure interaction (SSI) analysis is performed by the direct finite element method. In this paper, the earthquake is considered as the obliquely incident plane body wave arising from the truncated linearly elastic layered half space. An earthquake input method is developed for the time-domain three-dimensional SSI analysis. It consists of a new site response analysis method for free field and the viscous-spring artificial boundary condition for scattered field. The proposed earthquake input method can be implemented in the process of building finite element model of commercial software. It can result in the highly accurate solution by using a relatively small SSI model. The initial condition is considered for the nonlinear SSI analysis. The Daikai subway station is analyzed as an example. The effectiveness of the proposed earthquake input method is verified. The effect of the obliquely incident earthquake is studied.

Simplified analytical solution of tunnel cross section under oblique incident SH wave in layered ground

  • Huifang Li;Mi Zhao;Jingqi Huang;Weizhang Liao;Chao Ma
    • Earthquakes and Structures
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    • v.24 no.1
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    • pp.65-79
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    • 2023
  • A simplified analytical solution for seismic response of tunnel cross section in horizontally layered ground subjected to oblique incidence of SH wave is deduced in this paper. The proposed analytical solution consists of two main steps: free-field response in layered field and tunnel response. The free field responses of the layered ground are obtained by one-dimensional finite element method in time domain. The tunnel lining is treated as a thick-wall cylinder to calculate the tunnel response, which subject to free field stress. The analytical solutions are verified by comparing with the dynamic numerical results of two-dimensional ground-lining interaction analysis under earthquake in some common situations, which have a good agreement. Then, the appropriate range of the proposed analytical solution is analyzed, considering the height of the layered ground, the wavelength and incident angle of SH wave. Finally, by using the analytical solutions, the effects of the ground material, burial depth of the tunnel, and lining thickness and the slippage effect at the ground-lining interface on the seismic response of tunnels are investigated. The proposed solution could serve as a useful tool for seismic analysis and design of tunnels in layered ground.

Deep Local Multi-level Feature Aggregation Based High-speed Train Image Matching

  • Li, Jun;Li, Xiang;Wei, Yifei;Wang, Xiaojun
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.16 no.5
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    • pp.1597-1610
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    • 2022
  • At present, the main method of high-speed train chassis detection is using computer vision technology to extract keypoints from two related chassis images firstly, then matching these keypoints to find the pixel-level correspondence between these two images, finally, detection and other steps are performed. The quality and accuracy of image matching are very important for subsequent defect detection. Current traditional matching methods are difficult to meet the actual requirements for the generalization of complex scenes such as weather, illumination, and seasonal changes. Therefore, it is of great significance to study the high-speed train image matching method based on deep learning. This paper establishes a high-speed train chassis image matching dataset, including random perspective changes and optical distortion, to simulate the changes in the actual working environment of the high-speed rail system as much as possible. This work designs a convolutional neural network to intensively extract keypoints, so as to alleviate the problems of current methods. With multi-level features, on the one hand, the network restores low-level details, thereby improving the localization accuracy of keypoints, on the other hand, the network can generate robust keypoint descriptors. Detailed experiments show the huge improvement of the proposed network over traditional methods.

Technique of grouting in silty-fine sand with abundant water: Practice in Beijing

  • Liu, Jun;Zhang, Liang;Xue, Hongsong;You, Tian;Wu, Yuqian
    • Geomechanics and Engineering
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    • v.29 no.4
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    • pp.463-470
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    • 2022
  • In NATM tunnels, water inrush and tunnel collapse are often encountered in silty-fine sand with abundant water during excavation. Because of the special engineering properties of this stratum, grouting effect is difficult to achieve as expected, and it is a major problem in the field of civil engineering. Taking Beijing Metro Line 10 as a case, we applied PFC3D to simulate the process of grouting in this stratum. By analyzing the law of grout diffusing and porosity change under different grouting pressures, the study found that grouting was a process of splitting, and grouting pressure played an important role. The numerical results were verified by theoretical calculation analysis, and the grouting parameters were determined under the various grouting pressures for practice. After the excavation of this tunnel, the concretions in silty-fine sand are similar to the results of PFC3D simulation, which indicates that the grouting mechanism is confirmed by field observation further.

Mechanics model of novel compound metal damper based on Bi-objective shape optimization

  • He, Haoxiang;Ding, Jiawei;Huang, Lei
    • Earthquakes and Structures
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    • v.23 no.4
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    • pp.363-371
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    • 2022
  • Traditional metal dampers have disadvantages such as a higher yield point and inadequate adjustability. The experimental results show that the low yield point steel has superior energy dissipation hysteretic capacity and can be applied to seismic structures. To overcome these deficiencies, a novel compound metal damper comprising both low yield point steel plates and common steel plates is presented. The optimization objectives, including "maximum rigidity" and "full stress state", are proposed to obtain the optimal edge shape of a compound metal damper. The numerical results show that the optimized composite metal damper has the advantages such as full hysteresis curve, uniform stress distribution, more sufficient energy consumption, and it can adjust the yield strength of the damper according to the engineering requirements. In view of the mechanical characteristics of the compound metal damper, the equivalent model of eccentric cross bracing is established, and the approximate analytical solution of the yield strength and the yield displacement is proposed. A nonlinear simulation analysis is carried out for the overall aseismic capacity of three-layer-frame structures with a compound metal damper. It is verified that a compound metal damper has better energy dissipation capacity and superior seismic performance, especially for a damper with double-objective optimized shape.

Comparison of Solid Waste Management System between Beijing and Seoul (베이징과 서울의 폐기물 관리체계 비교연구)

  • Yoo, Kee-Young
    • Journal of the Korea Organic Resources Recycling Association
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    • v.23 no.3
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    • pp.42-50
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    • 2015
  • Beijing and Seoul are the capital of China and Korea, and political, economic, cultural, and tourist centers as well. Beijing is most likely to follow the footsteps of Seoul in the process of urbanization. The purpose of this study is to find out differences and improvements by comparing the solid waste management system between Beijing and Seoul. China classifies waste into urban waste, industrial waste and hazardous waste, which is the same as Korea did in 1980s. Beijing's policy directions in the waste management is similar to Seoul's in the early 1990s when Seoul strived to construct incinerators and landfill. Beijing's waste management achievements are also similar to Seoul's in that the ratio of recycling and incineration is high and that of landfill is low. Hence, it is expected for the waste management policies and achievement of two cities to resemble more and more. Financial burdens of government, indifference of citizens, and decentralized organizations of waste management might be the issues for Beijing to solve. In particular, to implement the user fee system and to encourage citizens to participate in waste separation discharge appear to be key issues in Beijing. Seoul should take a look at which the Beijing government itself collects waste in station and central area.

Enhanced photocatalytic oxidation of humic acids using Fe3+-Zn2+ co-doped TiO2: The effects of ions in aqueous solutions

  • Yuan, Rongfang;Liu, Dan;Wang, Shaona;Zhou, Beihai;Ma, Fangshu
    • Environmental Engineering Research
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    • v.23 no.2
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    • pp.181-188
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    • 2018
  • Photocatalytic oxidation in the presence of Fe-doped, Zn-doped or Fe-Zn co-doped $TiO_2$ was used to effectively decompose humic acids (HAs) in water. The highest HAs removal efficiency (65.7%) was achieved in the presence of $500^{\circ}C$ calcined 0.0010% Fe-Zn co-doped $TiO_2$ with the Fe:Zn ratio of 3:2. The initial solution pH value, inorganic cations and anions also affected the catalyst photocatalytic ability. The HAs removal for the initial pH of 2 was the highest, and for the pH of 6 was the lowest. The photocatalytic oxidation of HAs was enhanced with the increase of the $Ca^{2+}$ or $Mg^{2+}$ concentration, and reduced when concentrations of some anions increased. The inhibition order of the anions on $TiO_2$ photocatalytic activities was $CO{_3}^{2-}$ > $HCO_3{^-}$ > $Cl^-$, but a slightly promotion was achieved when $SO{_4}^{2-}$ was added. Total organic carbon (TOC) removal was used to evaluate the actual HAs mineralization degree caused by the $500^{\circ}C$ calcined 0.0010% Fe-Zn (3:2) co-doped $TiO_2$. For tap water added with HAs, the $UV_{254}$ and TOC removal rates were 57.2% and 49.9%, respectively. The $UV_{254}$ removal efficiency was higher than that of TOC because of the generation of intermediates that could significantly reduce the $UV_{254}$, but not the TOC.

A LysM Domain-Containing Protein LtLysM1 Is Important for Vegetative Growth and Pathogenesis in Woody Plant Pathogen Lasiodiplodia theobromae

  • Harishchandra, Dulanjalee Lakmali;Zhang, Wei;Li, Xinghong;Chethana, Kandawatte Wedaralalage Thilini;Hyde, Kevin David;Brooks, Siraprapa;Yan, Jiye;Peng, Junbo
    • The Plant Pathology Journal
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    • v.36 no.4
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    • pp.323-334
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    • 2020
  • Lysin motif (LysM) proteins are reported to be necessary for the virulence and immune response suppression in many herbaceous plant pathogens, while far less is documented in woody plant pathogens. In this study, we preliminarily characterized the molecular function of a LysM protein LtLysM1 in woody plant pathogen Lasiodiplodia theobromae. Transcriptional profiles revealed that LtLysM1 is highly expressed at infectious stages, especially at 36 and 48 hours post inoculation. Amino acid sequence analyses revealed that LtLysM1 was a putative glycoprotein with 10 predicted N-glycosylation sites and one LysM domain. Pathogenicity tests showed that overexpressed transformants of LtLysM1 displayed increased virulence on grapevine shoots in comparison with that of wild type CSS-01s, and RNAi transformants of LtLysM1 exhibited significantly decreased lesion length when compared with that of wild type CSS-01s. Moreover, LtLysM1 was confirmed to be a secreted protein by a yeast signal peptide trap assay. Transient expression in Nicotiana benthamiana together with protein immunoblotting confirmed that LtLysM1 was an N-glycosylated protein. In contrast to previously reported LysM protein Slp1 and OsCEBiP, LtLysM1 molecule did not interact with itself based on yeast two hybrid and co-immunoprecipitation assays. These results indicate that LtLysM1 is a secreted protein and functions as a critical virulence factor during the disease symptom development in woody plants.

Clinical Efficacy and Prognosis Factors for Advanced Hepatoblastoma in Children: A 6-year Retrospective Study

  • Zhang, Yi;Zhang, Wei-Ling;Huang, Dong-Sheng;Hong, Liang;Wang, Yi-Zhuo;Zhu, Xia;Hu, Hui-Min;Zhang, Pin-Wei;Yi, You;Han, Tao
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.8
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    • pp.4583-4589
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    • 2013
  • Objective: This study aimed to investigate the effect of multimodality treatment of advanced paediatric hepatoblastoma (HB) and the factors affecting prognosis. Methods: A total of 35 children underwent multimodality treatments consisting of chemotherapy, surgery, interventional therapy, and autologous peripheral blood stem cell transplantation. The patients were followed up every month. Results: Serum AFP levels in 33 out of 35 patients in this study were significantly increased (P = 0.0002). According to the statistical scatter plot, the values of serum AFP on the 25th, 50th, and 75th percentages were 1,210, 1,210 and 28,318 ng/dl, respectively. Of the 35 cases, 21 were stage IV. 18 cases were treated with systemic chemotherapy before surgery, and 3 cases with locally interventional chemotherapy before surgery. Statistical analysis showed that the preferred interventional treatment affected prognosis, and that there was a statistically significant difference (P = 0.024). Some 33 patients completed the follow-up, of which 17 were in complete remission (CR), 5 were in partial remission (PR), 1 became disease progressive (DP), and 10 died. The remission and overall survival rates were 66.7% (22/33) and 69.7% (23/33), respectively. Patients with the mixed HB phenotypes had worse prognoses than the epithelial phenotype (P < 0.001), and patients in stage IV had a lower survival rate than those in stage III (P < 0.001). Conclusion: Multimodality treatment can effectively improve remission rate and prolong the survival of children with advanced HB. In addition, alpha-fetoprotein (AFP), a tumor marker of liver malignant tumors, HB pathological classification, and staging are highly useful in predicting prognosis.

Immunohistochemical Localization of Endogenous IAA in Peach (Prunus persica L.) Fruit during Development

  • Zhang, Wei;Li, Yang;Shi, Mengya;Hu, Hao;Hua, Baoguang;Yang, Aizhen;Liu, Yueping
    • Horticultural Science & Technology
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    • v.33 no.3
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    • pp.317-325
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    • 2015
  • Peach (Prunus persica L.) is a model species for stone fruit studies within the Rosaceae family. Auxin plays an important role in the development of peach fruit. To reveal the distribution of auxin in the tissues of peach fruit, immunohistochemical localization of IAA was carried out in the seed, mesocarp, and endocarp in developing peach fruit using an anti-indole-3-acetic acid (anti-IAA) monoclonal antibody. A strong IAA signal was observed throughout the outer and inner integument during peach fruit development, and the distribution was zonal. The IAA signal was mainly focused in mucilage layers in the outer integument. The outer integument may function to produce or store IAA in the seed; a strong IAA signal was detected in the cells around the vascular tissue, whereas a weak IAA signal was located in the vascular tissues. In the mesocarp, the cells around the vascular bundle tissue gave rise to an IAA signal that increased in the late phase of fruit growth, which coincided with a significant increase in fruit growth. The distribution of IAA, however, was changed when fruit was treated with auxin transport inhibitors NPA (1-N-naphthylphthalamic acid) or TIBA (2, 3, 5-triiodobenzoic acid); in mesocarp tissues, an IAA signal was detected mainly in vessels of the treated fruit. During the critical period of endocarp lignification, the vessel lignification process was negatively correlated with IAA signal. The present results confirmed that the distribution of IAA was different in various tissues of peach fruit according to the developmental stage. This research provides cytological data for further study of the regulatory mechanism of auxin in peach fruit.