Interaction Analyses between Existing Pipeline and Quasi-Rectangular Tunneling in Clays

Zhiguo Zhang,Mengxi Zhang,Qihua Zhao,Lei Fang,Zhi Ding,Minzhi Shi 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.1

Previous researches about geoenvironmental disturbance caused by tunneling have mainly concentrated on the influences of circular tunnel construction, but minimal interesting is given to the quasi-rectangular shield tunneling. Considering the convergence deformation model for quasi-rectangular shield tunneling at excavation face, the simplified closed-form solution is put forward to evaluate the deformation behavior for underground pipeline caused by quasi-rectangular shield tunneling. Firstly, the free-field displacements induced by the quasi-rectangular shield excavation are estimated by the point source technique. Secondly, characterized by the Winkler foundation, the free-field displacements are applied to the pipeline structures and a simplified analytical solution is obtained for analyzing the deformation of adjacent pipeline induced by quasi-rectangular tunneling. Through the analyses of engineering cases, the comparison between analytical solution for the free-field deformation and measured data is conducted. Meanwhile, the numerical simulation technique and the physical modelling tests for the pipeline deformation are utilized to compare the simplified analytical results. In addition, the primary parameters are conducted for the interaction mechanics between quasi-rectangular tunneling and existing pipeline, such as the pipeline diameter, the geometry size and centerline depth of pipeline and tunnel, the structural physics modulus of pipeline, the compressive modulus of ground, and the ground loss parameter. The results of this study are of great significance for exploring the geomechanical effects induced by quasi-rectangular shield tunneling in clays.

MiR-204 acts as a potential therapeutic target in acute myeloid leukemia by increasing BIRC6-mediated apoptosis

( Zhiguo Wang ),( Hong Luo ),( Zehui Fang ),( Yanling Fan ),( Xiaojuan Liu ),( Yujing Zhang ),( Shuping Rui ),( Yafeng Chen ),( Luojia Hong ),( Jincheng Gao ),( Mei Zhang ) 생화학분자생물학회(구 한국생화학분자생물학회) 2018 BMB Reports Vol.51 No.9

Acute myeloid leukemia (AML) is one of the most common hematological malignancies all around the world. MicroRNAs have been determined to contribute various cancers initiation and progression, including AML. Although microRNA-204 (miR-204) exerts anti-tumor effects in several kinds of cancers, its function in AML remains unknown. In the present study, we assessed miR-204 expression in AML blood samples and cell lines. We also investigated the effects of miR-204 on cellular function of AML cells and the underlying mechanisms of the action of miR-204. Our results showed that miR-204 expression was significantly downregulated in AML tissues and cell lines. In addition, overexpression of miR-204 induced growth inhibition and apoptosis in AML cells, including AML5, HL-60, Kasumi-1 and U937 cells. Cell cycle analysis further confirmed an augmentation in theapoptotic subG1 population by miR-204 overexpression. Mechanistically, baculoviral inhibition of apoptosis protein repeat containing 6 (BIRC6) was identified as a direct target of miR-204. Enforcing miR-204 expression increased the luciferase activity and expression of BIRC6, as well as p53 and Bax expression. Moreover, restoration of BIRC6 reversed the pro-apoptotic effects of miR-204 overexpression in AML cells. Taken together, this study demonstrates that miR-204 causes AML cell apoptosis by targeting BIRC6, suggesting miR-204 may play an anti-carcinogenic role in AML and function as a novel biomarker and therapeutic target for the treatment of this disease. [BMB Reports 2018; 51(9): 444-449]

High step-up isolated forward-flyback DC/DC converter based on resonance with pulse frequency modulation

Zhang, Zhiguo,Liao, Mingyu,Jiang, Dongrong,Yang, Xiaobin,Li, Shan The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.2

A high step-up isolated forward-flyback DC-DC converter with pulse frequency modulation (PFM) is presented in this paper. The proposed converter has features of both a forward and a flyback converter and can deliver energy during the turn-on and turn-off intervals in a switching period. In addition, by utilizing resonance it can achieve zero-voltage switching (ZVS) for the primary switches and zero-current switching (ZCS) for the secondary rectifier diodes. All of the power semiconductors operate under soft switching conditions. The structure of the proposed converter is simple and easily implemented. It also provides a high step-up voltage gain. The current stresses of the power devices in PFM are lower than those in pulse width modulation (PWM). Therefore, the converter efficiency in PFM is higher than that in PWM. The operation principle and characteristic of the presented converter are described in detail, and the converter performances for PWM and PFM are compared. A 160 W hardware prototype has been built, and experimental results verify the validity of the theoretical analysis.

Analytical Prediction for Tunnel-Soil-Pile Interaction Mechanics based on Kerr Foundation Model

Zhiguo Zhang,Chengping Zhang,Kangming Jiang,Zhiwei Wang,Yunjuan Jiang,Qihua Zhao,Minghao Lu 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.6

Existing analytical method to predict tunneling-induced pile deformation is generally based on the Winkler foundation model that neglects shear effects of soil, which is not sufficient for engineering practice. A simplified solution based on Kerr foundation model is presented in this study to investigate the tunnel-soil-pile interaction. In order to improve the accuracy of the prediction for tunneling-induced free-field movements, the cavity contraction theory is utilized in the first stage which received a higher accuracy than the previous solution. In the second stage, the soil free-field displacement is imposed on the existing pile, and the simplified solution for pile deformation governed by the disturbance of passive displacement is established based on the Kerr foundation model, which can take account of the soil shear effects. The applicability and accuracy of the simplified solution are then verified by several cases including the reported analytical solution, centrifuge modeling tests and observed data in situ. Good agreements are obtained in the comparative analyses, which demonstrates that the proposed solution can serve as an alternative approach for conservatively estimating tunneling-induced pile deformation in the preliminary design in clay. Furthermore, the parametric analysis associated with the pile deformation has also been performed. As a result, it is of primarily theoretical and practical significance to investigate the influence of soil shear effects on the tunnel-soil-pile interaction mechanics.

An Empirical Study on the Validity of Corporate Coaching in China

LI Zhiguo,ZHANG Chunyu,ZHANG Junxi 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10

corporate coaching brought profound influence on numberiess individuals and organizations since it was introduced into Chinese in 1995, this paper focus on the validity of corporate coaching in China based on the outcome of 2000 questionnaires which come from all of 31 provinces of China and more than 18 industries; nearly 90 percents of the coaching clients undertake the responsibility for managerial effect; 73.6 percents of the coaching clients" age distribution lie in 26-40 years old. The data told us that the clients" personal ability, the relationship with others, and organizational performance can get improvement in different ways. We also found that Chinese traditional excellent culture and managerial intelligences can provide abundant nourishment for the long-term healthy development of corporate coaching in China.

Non-fragile Robust Finite-time H∞ Control for Nonlinear Stochastic Itô Systems Using Neural Network

Zhiguo Yan,Guoshan Zhang,Jiankui Wang 제어·로봇·시스템학회 2012 International Journal of Control, Automation, and Vol.10 No.5

This paper deals with the problem of non-fragile robust finite-time H∞ control for a class of uncertain nonlinear stochastic Itô systems via neural network. First, applying multi-layer feedback neural networks, the nonlinearity is approximated by linear differential inclusion (LDI) under state-space representation. Then, a sufficient condition is proposed for the existence of non-fragile state feedback finite-time H∞ controller in terms of matrix inequalities. Furthermore, the problem of non-fragile robust finite-time H∞ control is reduced to the optimization problem involving linear matrix inequalities (LMIs), and the detailed solving algorithm is given for the restricted LMIs. Finally, an example is given to illustrate the effectiveness of the proposed method.

Evaluating the Effectiveness and Efficiency of the Four-trillion Yuan Stimulus Package: Evidence from Stock Market Returns of Chinese Listed A Shares

Zhiguo Li,Xiaorong Zhang 연세대학교 동서문제연구원 2014 Global economic review Vol.43 No.4

Using stock returns of individual Chinese A shares as dependent variables, we confirm that the 2008 global financial crisis hit China through the demand channel and find that the four-trillion yuan stimulus package had a larger and more lasting effect on stimulating the real economy than on encouraging stock market speculation. The package, implemented with tremendous credit expansion in 2009 and 2010, is both effective and efficient in facilitating the financing of firms’ working capital, but has weaker effects on the financing of investments. Longterm capital allocation is not efficient in that it goes to firms that idiosyncratically invested heavily before the financial crisis but not to those that are in need of capital for investment determined by industry features. Specifically, state-owned companies are privileged in long-term financing but significantly underperform non-state-owned ones.

Preparation, Characterization and Photocatalytic Activity of Sodium Humate/Nano-TiO2 Coating on Glass Spheres for Flue Gas Denitrification

Zhiguo Sun,Jitao Yang,Li Zhang,Hongyong Xie 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.6

A new photocatalyst of sodium humate (HA–Na)/Nano-TiO2 coating on the glass spheres for flue gas denitrification (DeNOx) was prepared using the impregnation method. The HA–Na/TiO2 is characterized by Brunauer–Emmett–Teller (BET), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The photocatalytic activity of HA–Na/TiO2 on removing NOx was investigated in a self-designed photocatalytic reactor. The synergistic mechanism of HA–Na and TiO2 on DeNOx is also proposed and demonstrated. The experimental results indicate that specific surface area and average pore size of HA–Na are improved owing to the mixed TiO2 nanoparticles. The crystal structure of TiO2 has little change after mixing with HA–Na. Due to high photocatalytic performance of TiO2, NO was oxidized to NO2 and HNO3 eventually. On the other hand, HA–Na support can absorb and react with HNO3, which accelerates 10% of the catalytic reaction of TiO2 and the utilization of light source. The chemical and physiological activity of oxidized HA–Na are improved than the original humate. The HA–Na/TiO2 photocatalysts show great property on eliminating NOx because of the promoting effect between HA–Na and TiO2, and the NO removal efficiency can reach to 80% at the optimum condition.

Antioxidant Mechanism and Lipid Peroxidation Patterns in Leaves and Petals of Marigold in Response to Drought Stress

Zhiguo Tian,Fei Wang,Wene Zhang,Changming Liu,Xiuming Zhao 한국원예학회 2012 Horticulture, Environment, and Biotechnology Vol.53 No.3

In this study, malondialdehyde (MDA), relative conductivity (RC), superoxide anion (O2・-), hydrogen peroxide (H2O2), superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX) as well as ascorbic acid (AsA), glutation (GSH) and carotenoid (Car) were analyzed in plants under drought condition to investigate the enzymatic and non-enzymatic antioxidant defense mechanisms of leaves and petals, respectively. Two different drought resistance marigold cultivars (Tagetes erecta L. cv. Chokdee and Tagetes erecta L. cv. Discovery)treated with 6-day drought stress were used at early flowering stage. Results indicated that drought treatment increased MDA, RC, O2・- and H2O2 contents in the two cultivars, especially in drought-sensitive cultivar ‘Discovery’. In contrast,‘Chokdee’ had higher level antioxidative enzyme activities and more non-enzymatic antioxidants than those in ‘Discovery’. SOD, POD, CAT, APX activities and non-enzymatic antioxidants (GSH and AsA) in the leaves and petals were increased at the beginning treatment, and decreased later. The activity of CAT in leaves and petals, APX in petals and AsA in petals on day 6 after treatment were lower than those in control, while Car in the two cultivars decreased consistently during drought stress treatment. In addition, all the antioxidant enzyme activities in the leaves were higher than those in petals, but AsA and GSH were accumulated at lower levels in leaves than those in petals of the both cultivars. Furthermore, significant linear relationships were found between antioxidative enzymes and reactive oxygen species (ROS), as well as in non-enzymatic antioxidants and ROS. In conclusion, drought tolerance of ‘Chokdee’ was correlated with eliminating the O2・- and H2O2 and maintaining lower lipid peroxidation as well as higher membrane stability by increasing activities of antioxidative enzymes and the amount of non-enzymatic antioxidants. Furthermore, different drought response mechanisms were involved in leaves and petals of marigold under drought stress.

A unified framework for asymptotic and transient behavior of linear stochastic systems

Yan, Zhiguo,Park, Ju H.,Zhang, Weihai Elsevier 2018 Applied Mathematics and Computation Vol.325 No.-

<P><B>Abstract</B></P> <P>This paper is concerned with a unified framework for asymptotic and transient behavior of stochastic systems. In order to explain this problem explicitly, a concept of mean square (<I>γ, α</I>)-stability is first introduced and two stability criteria are derived. By utilizing an auxiliary definition of mean square (<I>γ</I>, T)-stability, the relations among mean square (<I>γ, α</I>)-stability, mean square (<I>γ</I>, T)-stability and finite-time stochastic stability are established. Subsequently, two new sufficient conditions for the existence of state and output feedback mean square (<I>γ, α</I>)-stabilization controllers are presented in terms of matrix inequalities. A numerical algorithm is given to obtain the relation between <I>γ</I> <SUB>min </SUB> and <I>α</I>. Finally, an example is given to illustrate our results.</P>