EIGENVALUE PROBLEMS FOR p-LAPLACIAN DYNAMIC EQUATIONS ON TIME SCALES

Guo, Mingzhou,Sun, Hong-Rui Korean Mathematical Society 2009 대한수학회보 Vol.46 No.5

In this paper, we are concerned with the following eigenvalue problems of m-point boundary value problem for p-Laplacian dynamic equation on time scales $(\varphi_p(u^{\Delta}(t)))^\nabla+{\lambda}h(t)f(u(t))=0,\;t\in(0,T)$, $u(0)=0,\varphi_p(u^{\Delta}(T))=\sum\limits_{i=1}^{m-2}a_i\varphi_p(u^{\Delta}(\xi_i))$, where $\varphi_p(u)=|u|^{p-2}$u, p > 1 and $\lambda$ > 0 is a real parameter. Under certain assumptions, some new results on existence of one or two positive solution and nonexistence are obtained for $\lambda$ evaluated in different intervals. Our work develop and improve many known results in the literature even for the continual case. In doing so the usual restriction that $f_0=lim_{u{\rightarrow}0}+f(u)/\varphi_p(u)$ and $f_\infty = lim_{u{\rightarrow}{\infty}}f(u)/\varphi_p({u})$ exist is removed. As an applications, an example is given to illustrate the main results obtained.

Eigenvalue problems for p-Laplacian dynamic equations on time scales

Mingzhou Guo,Hong-Rui Sun 대한수학회 2009 대한수학회보 Vol.46 No.5

In this paper, we are concerned with the following eigenvalue problems of m-point boundary value problem for p-Laplacian dynamic equation on time scales <수식> where φ_p(u) = |u|^p−2u, p > 1 and ¸ λ>0 is a real parameter. Under certain assumptions, some new results on existence of one or two positive solution and nonexistence are obtained for λ evaluated in different intervals. Our work develop and improve many known results in the literature even for the continual case. In doing so the usual restriction that f^0 = lim_(u→0)+ f(u)/φ_p(u) and f_∞ = lim_(u→∞) f(u)/φ_p(u) exist is removed. As an applications, an example is given to illustrate the main results obtained. In this paper, we are concerned with the following eigenvalue problems of m-point boundary value problem for p-Laplacian dynamic equation on time scales <수식> where φ_p(u) = |u|^p−2u, p > 1 and ¸ λ>0 is a real parameter. Under certain assumptions, some new results on existence of one or two positive solution and nonexistence are obtained for λ evaluated in different intervals. Our work develop and improve many known results in the literature even for the continual case. In doing so the usual restriction that f^0 = lim_(u→0)+ f(u)/φ_p(u) and f_∞ = lim_(u→∞) f(u)/φ_p(u) exist is removed. As an applications, an example is given to illustrate the main results obtained.

Hybrid simulation tests of high-strength steel composite K-eccentrically braced frames with spatial substructure

Tengfei Li,Mingzhou Su,Jiangran Guo 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.38 No.4

Based on the spatial substructure hybrid simulation test (SHST) method, the seismic performance of a high-strength steel composite K-eccentrically braced frame (K-HSS-EBF) structure system is studied. First, on the basis of the existing pseudostatic experiments, a numerical model corresponding to the experimental model was established using OpenSees, which mainly simulated the shear effect of the shear links. A three-story and five-span spatial K-HSS-EBF was taken as the prototype, and SHST was performed with a half-scale SHST model. According to the test results, the validity of the SHST model was verified, and the main seismic performance indexes of the experimental substructure under different seismic waves were studied. The results show that the hybrid simulation results are basically consistent with the numerical simulation results of the global structure. The deformation of each story is mainly concentrated in the web of the shear link owing to shear deformation. The maximum interstory drifts of the model structure during Strength Level Earthquake (SLE) and Maximum Considered Earthquake (MCE) meet the demands of interstory limitations in the Chinese seismic design code of buildings. In conclusion, the seismic response characteristics of the K-HSS-EBFs are successfully simulated using the spatial SHST, which shows that the K-HSS-EBFs have good seismic performance.

Seismic performance of eccentrically braced frames with high strength steel combination

Ming Lian,Mingzhou Su,Yan Guo 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.18 No.6

Eccentrically braced frames (EBFs) often use conventional steel with medium yield strength. This system requires structural members with large cross-sections for well seismic behavior, which leads to increased material costs. In eccentrically braced frames with high strength steel combination (HSS-EBFs), links use Q345 steel (specified nominal yield strength 345 MPa), braces use Q345 steel or high strength steel while other structural members use high strength steel (e.g., steel Q460 with the nominal yield strength of 460 MPa or steel Q690 with the nominal yield strength of 690 MPa). For this approach can result in reduced steel consumption and increased economic efficiency. Several finite element models of both HSS-EBFs and EBFs are established in this paper. Nonlinear hysteretic analyses and nonlinear time history analyses are conducted to compare seismic performance and economy of HSS-EBFs versus EBFs. Results indicate that the seismic performance of HSS-EBFs is slightly poorer than that of EBFs under the same design conditions, and HSS-EBFs satisfy seismic design codes and reduce material costs.

Estrogen Receptor-α Exacerbates EGF-Inducing Airway Remodeling and Mucus Production in Bronchial Epithelium of Asthmatics

Qin Lu,Yue Junqing,Guo Mingzhou,Zhang Cong,Fang Xiaoyu,Zhang Shengding,Bai Wenxue,Liu Xiansheng,Xie Min 대한천식알레르기학회 2023 Allergy, Asthma & Immunology Research Vol.15 No.5

Purpose: Although estrogen receptors (ERs) signal pathways are involved in the pathogenesis and development of asthma, their expressions and effects remain controversial. This study aimed to investigate the expressions of ERα and ERβ as well as their mechanisms in airway remodeling and mucus production in asthma. Methods: The expressions of ERα and ERβ in the airway epithelial cells of bronchial biopsies and induced sputum cells were examined by immunohistochemistry. The associations of ERs expressions with airway inflammation and remodeling were evaluated in asthmatic patients. In vitro, the regulations of ERs expressions in human bronchial epithelial cell lines were examined using western blot analysis. The epidermal growth factor (EGF)-mediated ligand-independent activation of ERα and its effect on epithelial-mesenchymal transitions (EMTs) were investigated in asthmatic epithelial cells by western blot, immunofluorescent staining, and quantitative real-time polymerase chain reaction. Results: ERα and ERβ were expressed on both bronchial epithelial cells and induced sputum cells, and the expressions showed no sex difference. Compared to controls, male asthmatic patients had higher levels of ERα on the bronchial epithelium, and there were cell-specific expressions of ERα and ERβ in induced sputum. The expression of ERα in the airway epithelium was inversely correlated to forced expiratory volume in 1 second (FEV1) % and FEV1/forced vital capacity. Severe asthmatic patients had significantly greater levels of ERα in the airway epithelium than mild-moderate patients. ERα level was positively correlated with the thickness of the subepithelial basement membrane and airway epithelium. In vitro, co-stimulation of interleukin (IL)-4 and EGF increased the expression of ERα and promoted its nuclear translocation. EGF activated the phosphorylation of ERα via extracellular signal-regulated kinase and c-Jun N-terminal kinase pathways. ERα knockdown alleviated EGF-mediated EMTs and mucus production in airway epithelial cells of asthma. Conclusions: ERα contributes to asthmatic airway remodeling and mucus production through the EGF-mediated ligand-independent pathway.