Research on Crossing Tunnels' Seismic Response Characteristics

Cong Liu,Li-min Peng,Ming-feng Lei,Yu-feng Li 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.11

A large-scale shaking table test system and corresponding numerical model are designed to study the seismic characteristics of crossing tunnels. The calculated results are in good agreement with experimental data, both the results suggest that: Loading the El-Centro seismic wave, the maximum acceleration in upper tunnel’s crossing center section is located in the crown, the maximum strain is located in the haunch; meanwhile, the maximum acceleration and strain in underpass tunnel’s cross center section are both located in the crown. Affected by the underpass tunnel, at the side wall bottom of the upper tunnel, tests data reveal that the crossing center’s maximum acceleration is reduced for 30.9% and the strain was enlarged 170% than the normal section. Affected by the upper tunnel, at the haunch of the underpass tunnel, tests data reveal the crossing center’s maximum acceleration is enlarged by 10.0% and the strain is 27.2% reduced than the normal section.

Principle Issues and Future Prospect on Sliding Arc Ablation of Metal Rail

Cong Haoxi,Zhou Yang,Zhaori Getu,Wang Yuxuan,Wei Haobo,Liu Zhaoling,Wang Jian,Zhang Li,Liu Hongshun,Li Qingmin 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.3

Arc ablation occurs when the armature passes over the surface of metal rail. Ablation not only seriously afects the service life, but also may cause the failure to launch. In this paper, the research status of sliding arc ablation technology is summarized from the mechanism of sliding arc ablation, the characterization method of sliding arc ablation degree, and the enhanced design of materials or structures. Three key issues that need to be further solved are listed: the infuence mechanism of sliding arc ablation on microstructure and properties of metal materials, the service properties evaluation and quantitative characterization methods of metal material, as well as the modifed and enhanced design of materials or structures. In response to those problems, eforts are needed to improve the awareness of sliding arc ablation with the theoretical basis and characterization methods, as well as guide the improvement and strengthening of rail design.

Model Tests of Jacked-Pile Penetration into Sand Using Transparent Soil and Incremental Particle Image Velocimetry

Cong Liu,Xiao-Wei Tang,Huanwei Wei,Pengpeng Wang,Honghua Zhao 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.4

This paper presents a series of physical modelling tests of jacked-pile penetration into sand, combining the transparent soil and incremental reliability-guided particle image velocimetry, which provides a non-intrusively internal deformation measurement approach to monitor the internal movement of soil caused by jacked-pile penetration. The difference between the full-model test and the half-model test was analyzed quantitatively for the first time. This paper aims to provide some new insight into the penetration mechanisms of different shapes of pile tip. In addition, the phenomenon of meta-stable sand plug in the process of jacked-pile penetration was studied by means of the method of partial replacement with dyed particles. Experimental evidence has shown that the boundary and interaction effect causes the experimental phenomenon of the half-model test to be different from the true condition. The shape effect of pile tip on the governing penetration mechanisms was discussed, and the disturbance effect of different shapes of pile tip was evaluated and compared based on a large number of model tests and published literatures. The paper intuitively demonstrates that the different penetration mechanism of flat-ended pile and cone-ended pile is mainly due to the formation of the meta-stable sand plug beneath the pile tip.

NEW INTEGRATED MULTI-ALGORITHM FUSION LOCALIZATION AND TRAJECTORY TRACKING FRAMEWORK OF AUTONOMOUS VEHICLES UNDER EXTREME CONDITIONS WITH NON-GAUSSIAN NOISES

Cong Liu,Hui Liu,Lijin Han,Changle Xiang 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.1

This paper proposes a novel integrated multi-algorithm fusion localization and trajectory tracking framework for autonomous vehicles under extreme conditions with non-Gaussian noises. Firstly, in order to solve the problem that GPS signals are interfered with non-Gaussian noises or lost, a localization method based on Particle Filter (PF) is designed, which takes full advantage of the reference objects position information and vehicle driving state information, thus realizing the self-localization for high-speed autonomous vehicles. Besides, considering the accumulated errors of the model-driven Inertial Measurement Unit (IMU) in the long-horizon positioning prediction, an online future driving state prediction algorithm based on multi-order variable-step Markov model (MM) is proposed to calculate the future vehicle position in scenarios without reference. The fusion of these two methods can give full play to their respective advantages, thus improving the accuracy and robustness of the whole localization algorithm in scenes with non-Gaussian noises. Then, the location information and the future driving state are applied to the trajectory tracking controller based on adaptive model predictive control (AMPC). Finally, the CarSim-Matlab/Simulink cGAOo-simulations results show the effectiveness of the proposed framework when GPS signal is interfered with non-Gaussian noises, which further improve the positioning accuracy and autonomous tracking stability.

Prediction of shape change of semi-elliptical surface crack by fatigue crack growth circles parameter

Cong Hao Liu,주석재 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.12

As a fatigue crack grows, its shape changes. The shape of the growing crack can be affected by the initial crack shape, the load typeand the fatigue crack growth rate of the material. Existing methods to predict the shape of the growing crack include finite element simulationtechniques, which typically require the computation of several hundred increments to get accurate results. This paper describes anew technique that uses growth circles to model the growing crack. Since the circles are perpendicular to the current crack front as wellas to the new crack front, it represents the real path of the fatigue crack well and yields more accurate results. The new technique is to beapplied to the case of a surface crack in a thick plate under tension or bending. The effects of the Paris–Erdogan exponent are also investigated.

Verification of multilevel octree grid algorithm of SN transport calculation with the Balakovo-3 VVER-1000 neutron dosimetry benchmark

Liu Cong,Zhang Bin,Wei Junxia,Tan Shuang 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.2

Neutron transport calculations are extremely challenging due to the high computational cost of large and complex problems. A multilevel octree grid algorithm (MLTG) of discrete ordinates method was developed to improve the modeling accuracy and simulation efficiency on 3-D Cartesian grids. The Balakovo-3 VVER-1000 neutron dosimetry benchmark is calculated to verify and validate this numerical technique. A simplified S2 synthetic acceleration is used in the MLTG calculation method to improve the convergence of the source iterations. For the triangularly arranged fuel pins, we adopt a source projection algorithm to generate pin-by-pin source distributions of hexagonal assemblies. MLTG provides accurate geometric modeling and flexible fixed source description at a lower cost than traditional Cartesian grids. The total number of meshes is reduced to 1.9 million from the initial 9.5 million for the Balakovo-3 model. The numerical comparisons show that the MLTG results are in satisfactory agreement with the conventional SN method and experimental data, within the root-mean-square errors of about 4% and 10%, respectively. Compared to uniform fine meshing, approximately 70% of the computational cost can be saved using the MLTG algorithm for the Balakovo-3 computational model.

A Cloud-computing-based Resource Allocation Model for University Resource Optimization

Cong Liu 보안공학연구지원센터(IJGDC) 2014 International Journal of Grid and Distributed Comp Vol.7 No.3

Application of a C-Type Filter Based LCFL Output Filter to Shunt Active Power Filters

Cong Liu,Ke Dai,Kewei Duan,Yong Kang 전력전자학회 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.6

This paper proposes and designs a new output filter called an LCFL filter for application to three phase three wire shunt active power filters (SAPF). This LCFL filter is derived from a traditional LCL filter by replacing its capacitor with a C-type filter, and then constructing an L-C-type Filter-L (LCFL) topology. The LCFL filter can provide better switching ripple attenuation capability than traditional passive damped LCL filters. The LC branch series resonant frequency of the LCFL filter is set at the switching frequency, which can bypass most of the switching harmonic current generated by a SAPF converter. As a result, the power losses in the damping resistor of the LCFL filter can be reduced when compared to traditional passive damped LCL filters. The principle and parameter design of the LCFL filter are presented in this paper, as well as a comparison to traditional passive damped LCL filters. Simulation and experimental results are presented to validate the theoretical analyses and effectiveness of the LCFL filter.

20世纪中国文学中人性与道德之关系研究

??(Liu Cong) 한국중어중문학회 2011 中語中文學 Vol.48 No.-

The problem of “Morality” was one of the most heavy topics in China in the beginning of 20th century because human nature had been imprisoned by the moral idea of old feudalism for too long time. In the whole 20th century, people constantly adjusted the relation between the morality and the human nature and try to make human nature reside poetically under the sky of morality. The conflict between human nature and social moral norms is an eternal topic accompanying the growing up of mankind, which exists for ever, and will become sharper and more evident in the tremendous changes of history. The cultural history of mankind shows us that the footsteps of human nature and morality should take each other as tropics: The establishment of moral norms should take human nature as a purpose, and the healthy development of human nature should also follow the necessary moral standards.

The Roles of Money’s Pride and Surprise Tag on the Use of Money

Cong Liu,최낙환 한국마케팅학회 2015 ASIA MARKETING JOURNAL Vol.17 No.3

The present research examined the interesting but less attended effects of pride- and surprise-tagged money on consumers’ spending decisions. Focusing on the unexpected money received in their daily life, we explored recipient’s judgments and responses toward pride-tagged money versus surprise-tagged, and identified differences in types of recipient’s consumption and spending behaviors between the pride- tagged money and the surprise-tagged money. Consumers tend to use the money associated with pride (vs. surprise) to reward their invested effort; as a result, they were more likely to buy a personal gift. Moreover, in the context of self-gift, consumers with pride-tagged money have showed a bigger positive difference between the intent to buy individual self-expressive products and the intent to buy social self-expressive products than those with surprise-tagged money. And the receipt of pride-tagged money activates motivation to express one’s individual self. Consumers who have received a sum of extra money tend to add the money into the current spendable income account and broaden the array of product category. And consumers with high arousal level of surprise triggered by receiving a sum of unpredictable money because of good luck show a smaller difference between the intent to buy individual self-expressive product and the intent to buy social self-expressive product than those with low level arousal in pride. Therefore, marketers should advertise their products in the respects of individual self-expression when their customers have pride-tagged money, and should advertise their products in the respects of social self-identity when they have surprise-tagged money by winning a large sum of unpredicted money like lottery winning.