Differential settlements in foundations under embankment load: Theoretical model and experimental verification

Wang, Changdan,Zhou, Shunhua,Wang, Binglong,Guo, Peijun,Su, Hui Techno-Press 2015 Geomechanics & engineering Vol.8 No.2

To research and analyze the differential settlements of foundations specifically, site investigations of existing railways and metro were firstly carried out. Then, the centrifugal test was used to observe differential settlements in different position between foundations on the basis of investigation. The theoretical model was established according to the stress diffusion method and Fourier method to establish an analytical solution of embankment differential settlement between different foundations. Finally, theoretical values and experimental values were analyzed comparatively. The research results show that both in horizontal and vertical directions, evident differential settlement exists in a limited area on both sides of the vertical interface between different foundations. The foundation with larger elastic modulus can transfer more additional stress and cause relatively less settlement. Differential settlement value decreases as the distance to vertical interface decreases. In the vertical direction of foundation, mass differential settlement also exists on both sides of the vertical interface and foundation with larger elastic modulus can transfer more additional stress. With the increase of relative modulus of different foundations, foundation with lower elastic modulus has larger settlement. Meanwhile, differential settlement is more obvious. The main error sources in theoretical and experimental values include: (a) different load form; (b) foundation characteristics differences; (c) modulus conversion; (d) effect of soil internal friction.

Settlement behavior and controlling effectiveness of two types of rigid pile structure embankments in high-speed railways

Wang, Changdan,Zhou, Shunhua,Wang, Binglong,Guo, Peijun,Su, Hui Techno-Press 2016 Geomechanics & engineering Vol.11 No.6

In this study, a series of geotechnical centrifugal tests were conducted to investigate the effectiveness of settlement control of two types of rigid pile structure embankments (PRSE) in collapsible loess under high-speed railway embankments. The research results show that ground reinforcement is required to reduce the post-construction settlement and settlement rate of the embankments. The rigid pile structure embankments using rigid piles can substantially reduce the embankment settlement in the construction of embankments on collapsible loess, and the efficiency in settlement reduction is affected by the pile spacing. The pile-raft structure embankments (PRSE) have much stronger ability in terms of the effectiveness of settlement control, while the pile-geogrid structure embankments (PGSE) provides rapid construction as well as economic benefits. Rational range of pile spacing of PRSE and PGSE are suggested based on the requirements of various railways design speeds. Furthermore, the time effectiveness of negative skin friction of piles and the action of pile-cap setting are also investigated. The relevant measures for improving the bearing capacity and two parts of transition zone forms as positive control mean have been suggested.

Inhibition of Tumor Growth by Recombinant Adenovirus Containing Human Lactoferrin through Inducing Tumor Cell Apoptosis in Mice Bearing EMT6 Breast Cancer

Jianjie Wang,Qingwang Li,Yetao Ou,Zengsheng Han,Kun Li,Peijun Wang,Shaobo Zhou 대한약학회 2011 Archives of Pharmacal Research Vol.34 No.6

Human lactoferrin (hLTF), an 80-kDa iron-binding glycoprotein, has antitumor activity. In this study, a recombinant adenovirus containing the human lactoferrin cDNA (ad-rhLTF) was constructed and its effect on tumor growth was investigated in mice bearing EMT6 breast cancer. Ad-rhLTF was injected seven times within 14 days into the tumor site at two concentrations (10^8 and 5 × 10^8 pfu/mL) in mice bearing EMT6 breast cancer. Injected ad-rhLTF had considerable cytotoxicity on mice breast cancer, and significantly reducing the weight of tumor produced and increasing the tumor inhibition rate up to 52.64%. The presence of apoptotic cells was confirmed using TUNEL staining and flow cytometry assays. At the same time, RTPCR and Western blot analyses demonstrated that ad-rhLTF also decreased expression of Bcl-2 and increased Bax and caspase 3 expressions. Therefore, we conclude that ad-rhLTF inhibits tumor growth by inducing tumor cell apoptosis in mice with breast cancer by triggering the mitochondrial-dependent pathway and activation of caspase 3. The results indicate that adrhLTF might be a promising drug for breast cancer gene therapy.

Modeling and Analyzing for Magnetic Field of Segmented Surface-Mounted PM Motors with Skewed Poles

Wang Huimin,Guan Peijun,Liu Shu,Wu Shuang,Shi Tingna,Guo Liyan 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.2

The skewed PM (permanent magnet) in the axial direction and the segmented PM in the circumferential direction, can reduce the cogging torque of the permanent magnet synchronous motor (PMSM). In this paper, the magnetization expression, which can be applied to diff erent circumferential sectioning modes, is derived. The quasi-3D magnetic fi eld analytical model suitable for diff erent circumferential and axial segmentation modes is proposed. The magnetic fi eld, cogging torque, back-EMF, and electromagnetic torque are obtained by the proposed modeling. The accuracy of the analytical method is verifi ed by 3D fi nite-element analysis. Finally, the modeling is used to analyze the variation of electromagnetic performance with diff erent radial skew angle and axial segments. The proposed modeling can shorten the calculation time, and analyze the variation law of motor performance with PM segmentation and skew comprehensively. It provides a reference for the design and optimization of segmented PMSM with skewed poles and has great signifi cance for improving motor performance.

LINEAR WEINGARTEN HYPERSURFACES IN RIEMANNIAN SPACE FORMS

Chao, Xiaoli,Wang, Peijun Korean Mathematical Society 2014 대한수학회보 Vol.51 No.2

In this note, we generalize the weak maximum principle in [4] to the case of complete linear Weingarten hypersurface in Riemannian space form $\mathbb{M}^{n+1}(c)$ (c = 1, 0,-1), and apply it to estimate the norm of the total umbilicity tensor. Furthermore, we will study the linear Weingarten hypersurface in $\mathbb{S}^{n+1}(1)$ with the aid of this weak maximum principle and extend the rigidity results in Li, Suh, Wei [13] and Shu [15] to the case of complete hypersurface.

Linear Weingarten hypersurfaces in Riemannian space forms

Xiaoli Chao,Peijun Wang 대한수학회 2014 대한수학회보 Vol.51 No.2

In this note, we generalize the weak maximum principle in [4] to the case of complete linear Weingarten hypersurface in Riemannian space form Mn+1(c) (c = 1, 0,−1), and apply it to estimate the norm of the total umbilicity tensor. Furthermore, we will study the linear Weingarten hypersurface in Sn+1(1) with the aid of this weak maximum principle and extend the rigidity results in Li, Suh, Wei [13] and Shu [15] to the case of complete hypersurface.

Strength of connection fixed by TOBs considering out-of-plane tube wall deformation-Part 1: Tests and numerical studies

Tuoya Wulan,Peijun Wang,Chengxin Xia,Xinyu Liu,Mei Liu,Fangzhou Liu,Ou Zhao,Lulu Zhang 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.42 No.1

This paper presents a study on the behavior of a bolted T-stub to square tube connection using Thread-fixed Oneside Bolts (TOBs) through tests and numerical simulations. It outlines a research work of four connections with focus on the failure modes and strengths of the connection under tensile load. It was observed that the thread anchor failure caused by shear failure of hole threads controlled the final failure of the connection in the tests. Meanwhile, the out-of-plane deformation of tube wall resulted in the contact separation between hole threads and bolt threads, which in turn reduced the shear strength of hole threads. Finite element models (FEMs) allowing for the configuration details of the TOBs fixed connection are then developed and compared with the test results. Subsequently, the failure mechanism of hole threads and stress distribution of each component are analyzed based on FEM results. It was concluded that the ultimate strength of connection was not only concerned with the shear strength of hole threads, but also was influenced by the plastic out-of-plane deformation of tube wall. These studies lay a foundation for the establishment of suitable design methods of this type of connection.

Altered Activity and Functional Connectivity of Superior Temporal Gyri in Anxiety Disorders: A Functional Magnetic Resonance Imaging Study

Xiaohu Zhao,Qian Xi,Peijun Wang,Chunbo Li,Hongjian He 대한영상의학회 2014 Korean Journal of Radiology Vol.15 No.4

Objective: The prior functional MRI studies have demonstrated significantly abnormal activity in the bilateral superior temporal gyrus (STG) of anxiety patients. The purpose of the current investigation was to determine whether the abnormal activity in these regions was related to a loss of functional connectivity between these regions. Materials and Methods: Ten healthy controls and 10 anxiety patients underwent noninvasive fMRI while actively listening to emotionally neutral words alternated by silence (Task 1) or threat-related words (Task 2). The participants were instructed to silently make a judgment of each word’s valence (i.e., unpleasant, pleasant, or neutral). A coherence analysis was applied to the functional MRI data to examine the functional connectivity between the left and the right STG, which was selected as the primary region of interest on the basis of our prior results. Results: The data demonstrated that the anxiety patients exhibited significantly increased activation in the bilateral STG than the normal controls. The functional connectivity analysis indicated that the patient group showed significantly decreased degree of connectivity between the bilateral STG during processing Task 2 compared to Task 1 (t = 2.588, p = 0.029). In addition, a significantly decreased connectivity was also observed in the patient group compared to the control group during processing Task 2 (t = 2.810, p = 0.012). Conclusion: Anxiety patients may exhibit increased activity of the STG but decreased functional connectivity between the left and right STG, which may reflect the underlying neural abnormality of anxiety disorder, and this will provide new insights into this disease.

Simplified method for prediction of elastic-plastic buckling strength of web-post panels in castellated steel beams

Mei Liu,Kangrui Guo,Peijun Wang,Chao Lou,Yue Zhang 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.25 No.6

Elastic-plastic shear buckling behaviors of the web-post in a Castellated Steel Beam (CSB) with hexagonal web openings under vertical shear force were investigated further using Finite Element Model (FEM) based on a sub-model, which took the upper part of the web-post under horizontal shear force to represent the whole web-post under vertical shear force. A simplified design method for the web-post elastic-plastic shear buckling strength was proposed based on simulation results of the sub-model. Proper boundary conditions were applied to the sub-model to assure that its behaviors were identical to those of the whole web-post. The equation to calculate the thin plate elastic shear buckling strength was adopted as the basic form to build the design equation for elastic-plastic buckling strength of the sub-model. Parameters that might affect the elastic-plastic shear buckling strength of the whole web-post were studied. After obtaining the vertical shear buckling strength of a sub-model through FEM, the shear buckling coefficient k can be obtained through the back analysis. A practical calculation method for k was proposed through curving fitting the parameter study results. The elastic-plastic shear buckling strength of the web-post calculated using the proposed shear buckling coefficient k agreed well with that obtained from the FEM and test results. And it was more precise than those obtained from EC3 based on the strut model.

Post-buckling behaviours of axially restrained steel columns in fire

Guo-Qiang Li,Peijun Wang,Hetao Hou 국제구조공학회 2009 Steel and Composite Structures, An International J Vol.9 No.2

This paper presents a simplified model to study post-buckling behaviours of the axially restrained steel column at elevated temperatures in fire. The contribution of axial deformation to the curvature of column section is included in theoretical equations. The possible unloading at the convex side of the column when buckling occurs is considered in the stress-strain relationship of steel at elevated temperatures. Parameters that affect structural behaviours of the axial restrained column in fire are studied. The axial restraint cause an increase in the axial force before the column buckles; the buckling emperature of restrained columns will be lower than non-restrained steel columns. However, the axial force of a restrained column decreases after the column buckles with the elevation of temperatures, so make use of the post-buckling behaviour can increase the critical temperature of restrained columns. Columns with temperature gradient across the section will produce lower axial force at elevated temperatures.