Experimental investigation on a freestanding bridge tower under wind and wave loads

Xiaodong Bai,Anxin Guo,Hao Liu,Wenli Chen,Gao Liu,Tianchen Liu,Shangyou Chen,Hui Li 국제구조공학회 2016 Structural Engineering and Mechanics, An Int'l Jou Vol.57 No.5

Long-span cross-strait bridges extending into deep-sea waters are exposed to complex marine environments. During the construction stage, the flexible freestanding bridge towers are more vulnerable to environmental loads imposed by wind and wave loads. This paper presents an experimental investigation on the dynamic responses of a 389-m-high freestanding bridge tower model in a test facility with a wind tunnel and a wave flume. An elastic bridge model with a geometric scale of 1:150 was designed based on Froude similarity and was tested under wind-only, wave-only and wind-wave combined conditions. The dynamic responses obtained from the tests indicate that large deformation under resonant sea states could be a structural challenge. The dominant role of the wind loads and the wave loads change according to the sea states. The joint wind and wave loads have complex effects on the dynamic responses of the structure, depending on the approaching direction angle and the fluid-induced vibration mechanisms of the waves and wind

A zeolite family with expanding structural complexity and embedded isoreticular structures

Guo, Peng,Shin, Jiho,Greenaway, Alex G.,Min, Jung Gi,Su, Jie,Choi, Hyun June,Liu, Leifeng,Cox, Paul A.,Hong, Suk Bong,Wright, Paul A.,Zou, Xiaodong Nature Publishing Group, a division of Macmillan P 2015 Nature Vol.524 No.7563

The prediction and synthesis of new crystal structures enable the targeted preparation of materials with desired properties. Among porous solids, this has been achieved for metal–organic frameworks, but not for the more widely applicable zeolites, where new materials are usually discovered using exploratory synthesis. Although millions of hypothetical zeolite structures have been proposed, not enough is known about their synthesis mechanism to allow any given structure to be prepared. Here we present an approach that combines structure solution with structure prediction, and inspires the targeted synthesis of new super-complex zeolites. We used electron diffraction to identify a family of related structures and to discover the structural ‘coding’ within them. This allowed us to determine the complex, and previously unknown, structure of zeolite ZSM-25 (ref. 8), which has the largest unit-cell volume of all known zeolites (91,554 cubic ångströms) and demonstrates selective CO<SUB>2</SUB> adsorption. By extending our method, we were able to predict other members of a family of increasingly complex, but structurally related, zeolites and to synthesize two more-complex zeolites in the family, PST-20 and PST-25, with much larger cell volumes (166,988 and 275,178 cubic ångströms, respectively) and similar selective adsorption properties. Members of this family have the same symmetry, but an expanding unit cell, and are related by hitherto unrecognized structural principles; we call these family members embedded isoreticular zeolite structures.

Numerical analysis of stress wave of projectile impact composite laminate

Zhangxin Guo,Weijing Niu,Junjie Cui,Gin Boay Chai,Yongcun Li,Xiaodong Wu 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.87 No.2

The three-dimensional Hashin criterion and user subroutine VUMAT were used to simulate the damage in the composite layer, and the secondary stress criterion was used to simulate the interlayer failure of the cohesive element of the bonding layer and the propagation characteristics under the layer. The results showed that when the shear stress wave (shear wave) propagates on the surface of the laminate, the stress wave attenuation along the fiber strength direction is small, and thus producing a large stress profile. When the compressive stress wave (longitudinal wave) is transmitted between the layers, it is reflected immediately instead of being transmitted immediately. This phenomenon occurs only when the energy has accumulated to a certain degree between the layers. The transmission of longitudinal waves is related to the thickness and the layer orientation. Along the symmetry across the thickness direction, the greater is the stress amplitude along the layer direction. Based on the detailed investigation on the impact on various laminated composites carried out in this paper, the propagation characteristics of stress waves, the damage and the destruction of laminates can be explained from the perspective of stress waves and a reasonable layering sequence of the composite can be designed against damage and failure from low velocity impact.

Numerical evaluation of hypothetical core disruptive accident in full-scale model of sodium-cooled fast reactor

Zhihong Guo,Xiaodong Chen,Guoqing Hu 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.6

A hypothetical core destructive accident (HCDA) has received widespread attention as one of the mostserious accidents in sodium-cooled fast reactors. This study combined recent advantages in numericalmethods to realize realistic modeling of the complex fluidestructure interactions during HCDAs in a fullscale sodium-cooled fast reactor. The multi-material arbitrary LagrangianeEulerian method is used todescribe the fluidestructure interactions inside the container. Both the structural deformations and plugrises occurring during HCDAs are evaluated. Two levels of expansion energy are considered with twodifferent reactor models. The simulation results show that the container remains intact during an accident with small deformations. The plug on the top of the container rises to an acceptable level after thesealing between the it and its support is destroyed. The methodology established in this study provides areliable approach for evaluating the safety feature of a container design.

A Novel 3-D Imaging Configuration Exploiting Synthetic Aperture Ladar

Liang Guo,Yinli Huang,Xiaozhen Li,Xiaodong Zeng,Yu Tang,Mengdao Xing 한국광학회 2017 Current Optics and Photonics Vol.1 No.6

Traditional three-dimensional (3-D) laser imaging systems are based on real aperture imaging technology,whose resolution decreases as the range increases. In this paper, we develop a novel 3-D imaging techniquebased on the synthetic aperture technology in which the imaging resolution is significantly improved anddoes not degrade with the increase of the range. We consider an imaging laser radar (ladar) system usingthe floodlight transmitting mode and multi-beam receiving mode. High 3-D imaging resolutions areachieved by matched filtering the linear frequency modulated (LFM) signals respectively in range, syntheticaperture along-track, and the real aperture across-track. In this paper, a novel 3-D imaging signal modelis given first. Because of the motion during the transmission of a sweep, the Doppler shift induced bythe continuous motion is taken into account. And then, a proper algorithm for the 3-D imaging geometryis given. Finally, simulation results validate the effectiveness of the proposed technique.

Experimental Study on Compressibility and Microstructure of Loess Solidified by Permeable Polymer

Chengchao Guo,Xiaodong Yang,Weifan Zhao 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.5

This study aims to investigate the compressive and microstructural properties of loess beforeand after treatment with a new permeable polymer. To enhance the compressive properties ofloess, specimens were infused with the new polymer, and one-dimensional consolidation testswere performed to assess the compressibility of solidified loess (SL) and unsolidified loess (UL)at different water contents. Additionally, the microstructure and pore morphology of UL andSL were examined using a scanning electron microscope (SEM) and the Particles (Pores) andCracks Analysis System (PCAS). Statistical methods were employed to analyze the relationshipsbetween microstructural parameters and compression modulus. The experimental resultsdemonstrate a significant improvement in the compressibility of loess when treated with thepolymer. The complexity of pore structure and variability in pore size are reduced, leading toa more uniform pore distribution. Moreover, all microstructural parameters exhibit a strongcorrelation with the compression modulus. The results pertaining to the compressive andmicrostructural properties of loess reinforced with permeable polymer grouting can provideinsights into the variations in the curing effect, serving as a theoretical foundation for theapplication of permeable polymer in loess treatment.

High-Fidelity Simulation and Performance Analysis of Twin-Spool Turbofan Engine Based on Multi-dynamics Approach

Chaochao Guo,Youchao Sun,Longbiao Li,Xiaodong Zhu 한국항공우주학회 2024 International Journal of Aeronautical and Space Sc Vol.25 No.4

To build a reusable and flexible general simulation platform for turbofan engines, this paper constructs a general turbofan engine simulation platform that utilizes the hierarchical design method oriented to graphical module objects. According to the inertia of the engine rotor and the storage effect of gas mass and energy in volumes, the performance parameters at the typical cross-section of the engine are obtained by solving the first-order differential equations of mass, momentum, and energy, and the component-level nonlinear dynamic mathematical model of the turbofan engine is established. This model is used to simulate the characteristic of a certain type of engine, and the results show that the steady-state error is less than 1.1% by comparing the simulation results with the experimental data. The average calculation time for a single flow path in the multi-dynamic model is 0.512 s and the multi-dynamic model exhibits rapid response speed during transient thrust variations with an adjustment time of less than 3 s. This modeling avoids large-scale iteration when solving nonlinear equations, improves the calculation speed of the full-range turbofan engine simulation program, and provides a viable option for constructing a computational model of a twin-spool turbofan engine that may be used in simulation studies.

Citrus Genetic Transformation with Interest Target Genes for Cultivar Improvement

Wenwu Guo,Yanxin Duan,Dingli Li,Xin Liu,Bin Tan,Xiaodong Cai,Xiuxin Deng 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

A Sense Embedding of Deep Convolutional Neural Networks for Sentiment Classification

Zhijian Cui,Xiaodong Shi,Yidong Chen,Yinmei Guo 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.11

Sentiment classification task has attracted considerable interest as sentiment information is crucial for many natural language processing (NLP) applications. The goal of sentiment classification is to predict the overall emotional polarity of a given text. Previous work has demonstrate the remarkable performance of Convolutional Neural Network (CNN). However, nearly all this work assumes a single word embedding for each word type, ignoring polysemy and thus inevitably casting negative impact on the downstream tasks. We extend the Skip-gram model to learn multiple sense embeddings for the word types, catering to introduce sense-based embeddings for CNN during sentiment classification. Instead of using the pipeline method to learn multiple sense embeddings of a word type, the sense discrimination and sense embedding learning for each word type are performed jointly based upon the semantics of its contextual words. We validate the effectiveness of the method on the commonly used datasets. Experiment results show that our method are able to improve the quality of sentiment classification when comparing with several competitive baselines.

Altered lipid metabolism promoting cardiac fibrosis is mediated by CD34+ cell-derived FABP4+ fibroblasts

Du Luping,Wang Xuyang,Guo Yan,Tao Tingting,Wu Hong,Xu Xiaodong,Zhang Bohuan,Chen Ting,Xu Qingbo,Guo Xiaogang 생화학분자생물학회 2024 Experimental and molecular medicine Vol.56 No.-

Hyperlipidemia and hypertension might play a role in cardiac fibrosis, in which a heterogeneous population of fibroblasts seems important. However, it is unknown whether CD34+ progenitor cells are involved in the pathogenesis of heart fibrosis. This study aimed to explore the mechanism of CD34+ cell differentiation in cardiac fibrosis during hyperlipidemia. Through the analysis of transcriptomes from 50,870 single cells extracted from mouse hearts and 76,851 single cells from human hearts, we have effectively demonstrated the evolving cellular landscape throughout cardiac fibrosis. Disturbances in lipid metabolism can accelerate the development of fibrosis. Through the integration of bone marrow transplantation models and lineage tracing, our study showed that hyperlipidemia can expedite the differentiation of non-bone marrow-derived CD34+ cells into fibroblasts, particularly FABP4+ fibroblasts, in response to angiotensin II. Interestingly, the partial depletion of CD34+ cells led to a notable reduction in triglycerides in the heart, mitigated fibrosis, and improved cardiac function. Furthermore, immunostaining of human heart tissue revealed colocalization of CD34+ cells and fibroblasts. Mechanistically, our investigation of single-cell RNA sequencing data through pseudotime analysis combined with in vitro cellular studies revealed the crucial role of the PPARγ/Akt/Gsk3β pathway in orchestrating the differentiation of CD34+ cells into FABP4+ fibroblasts. Through our study, we generated valuable insights into the cellular landscape of CD34+ cell-derived cells in the hypertrophic heart with hyperlipidemia, indicating that the differentiation of non-bone marrow-derived CD34+ cells into FABP4+ fibroblasts during this process accelerates lipid accumulation and promotes heart failure via the PPARγ/Akt/Gsk3β pathway.