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Search Results: 1 - 10 of 16832 matches for " Zhong Zhengqiang "
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Nonlinear Forced Vibration Analysis for Thin Rectangular Plate on Nonlinear Elastic Foundation
Zhong Zhengqiang,Xiao Yonggang,Yang Cuiping
Research Journal of Applied Sciences, Engineering and Technology , 2013,
Abstract: Nonlinear forced vibration is analyzed for thin rectangular plate with four free edges on nonlinear elastic foundation. Based on Hamilton variation principle, equations of nonlinear vibration motion for thin rectangular plate under harmonic loads on nonlinear elastic foundation are established. In the case of four free edges, viable expressions of trial functions for this specification are proposed, satisfying all boundary conditions. Then, equations are transformed to a system of nonlinear algebraic equations by using Galerkin method and are solved by using harmonic balance method. In the analysis of numerical computations, the effect on the amplitude-frequency characteristic curve due to change of the structural parameters of plate, parameters of foundation and parameters of excitation force are discussed.
Effects of temperature on Brontispa longissima population growth

ZHONG Yihai,LI Hong,LIU Kui,WEN Haibo,JIN Qi'an,PENG Zhengqiang,

应用生态学报 , 2005,
Abstract: The study on the development, survival and reproduction of Brontispa longissima at 5 different temperature (16, 20, 24, 28, 32 degrees C) showed that the threshold temperature and effective accumulative temperature for the whole generations of Brontispa longissima were 11.08 degrees C and 966.22 degrees C, respectively, and 4-5 generations could occur in a year in Danzhou, Hainan Province. One generation had the highest survival rate (92.5%) at 28 degrees C, but failed to survive at 32 degrees C. Brontispa longissimna reared at 28 degrees C had the greatest intrinsic increasing rate (r(m) = 0.0260), finite increasing capacity (lamda = 1.0263), and population trend index (I = 50.8). The shortest mean generation time (123.1 d) and population doubling time (26.7 d) were obtained at 20 degrees C and 28 degrees C, respectively. The temperature from 24 degrees C to 28 degrees C was suitable for the development and reproduction of Brontispa longissima.
Bivariate Degradation Modeling Based on Gamma Process
Jinglun Zhou,Zhengqiang Pan,Quan Sun
Lecture Notes in Engineering and Computer Science , 2010,
Joint Accelerated Failure Mode Modeling of Degradation and Traumatic Failure Times
Zhengqiang Pan,Jinglun Zhou,Peng Zhao
Lecture Notes in Engineering and Computer Science , 2010,
Sliding Mode Control for Electrohydrostatic Actuator
Shi Zhengqiang,Tang Zhiyong,Pei Zhongcai
Journal of Control Science and Engineering , 2014, DOI: 10.1155/2014/481970
Abstract: Electrohydrostatic actuator (EHA) is a new actuator for next generation aircraft actuation system. This actuator is essentially a nonlinear system; response speed and accuracy are the main consideration. We use sliding mode control for this nonlinear system in this paper. The variable structure filter (VSF) is introduced to obtain the unmeasured states. Derivation of the VSF gain based on the reaching law is presented in this paper. To improve the response speed and accuracy, a nonlinear function is introduced to construct the nonlinear sliding surface using the estimated states generated by VSF. Simulation results show that low settling time and quick response are obtained by using the nonlinear sliding surface. 1. Introduction Conventional aircraft hydraulic actuation systems are driven by the central hydraulic station. A major disadvantage of this arrangement is that the fuselage of the aircraft filled with hydraulic pipeline. The complicated pipelines increase the vulnerable areas and decrease the chances of survival in battlefield. The power by wire (PBW) technology is introduced to solve this problem. The central hydraulic station and the complicated pipelines can be removed by using this technology [1–3]. The key component is the so-called PBW actuators. The electrohydrostatic actuator (EHA) is an important one among these actuators. Architecture of the EHA can be illustrated by Figure 1. Figure 1: Schematic diagram of EHA. In Figure 1 the brushless dc motor (1) is controlled to provide energy for the bidirection hydraulic pump (2). Then the controlled pump drives the symmetrical cylinder (8) to a given position. The pressure measurement (7) is used to compensate the load disturbance. The controller uses position measurement (9) to construct position close-loop. The accumulator (4) is used to collect and store leakage oil. Another role of the accumulator is to guarantee the positive pressure in the return oil circuit. Check valve (3) is used to implement the logic judgment according to system pressures. Bypass valve (5) is used to isolate the actuator when system fails. (6) are safety valves. Mathematical model of the EHA is used to obtain the control laws. However design control laws to obtain desired performance of the controlled closed-loop system is a difficult task. The main reason for this problem is that the unknown disturbances, plant parameters variation, and unmodeled dynamics cannot be considered in the mathematical model. A robust control method is needed under these circumstances. One particular approach to robust controller design
Optimal design for step-stress accelerated test with random discrete stress elevating times based on gamma degradation process
Morteza Amini,Soudabeh Shemehsavar,Zhengqiang Pan
Statistics , 2014,
Abstract: Recently, a step-stress accelerated degradation test (SSADT) plan, in which the stress level is elevated when the degradation value of a product crosses a pre-specified value, was proposed. The times of stress level elevating are random and vary from product to product. In this paper we extend this model to a more economic plan. The proposed extended model has two economical advantages compared with the previous one. The first is that the times of stress level elevating in the new model are identical for all products, which enable us to use only one chamber (oven) for testing all test units. The second is that, the new method does not require continuous inspection and to elevate the stress level, it is not necessary for the experimenter to inspect the value of the degradation continually. The new method decrease the cost of measurement and also there is no need to use electronic sensors to detect the first passage time of the degradation to the threshold value in the new method. We assume that the degradation path follows a gamma process. The stress level is elevated as soon as the measurement of the degradation of one of the test units, at one of the specified times, exceeds the threshold value. Under the constraint that the total experimental cost does not exceed a pre-specified budget, the optimal settings including the optimal threshold value, sample size, measurement frequency and termination time are obtained by minimizing the asymptotic variance of an estimated quantile of the lifetime distribution of the product. A case study is presented to illustrate the proposed method.
A Peptidomic Analysis of the Potential Comorbidity Biomarkers for Type 2 Diabetes Mellitus and Alzheimer’s Disease  [PDF]
Zhengqiang Du, Jian Hua, Dalin Song
Health (Health) , 2019, DOI: 10.4236/health.2019.116065
Abstract: Objective: To investigate the potential comorbidity biomarkers for Type 2 Diabetes Mellitus (T2DM) and Alzheimer’s disease (AD). Methods: This is a randomized case-control study. There are three groups: 1) normal control group included 32 healthy elderly people in the hospital physical examination; 2) 30 patients with T2DM group; and 3) AD group has 28 cases. On-line reversed-phase liquid chromatography separation, tandem mass spectrometry analysis and iTRAQ quantification were used for identification of peptidomic analysis, then detection of three comorbidity biomarkers might be associated with T2DM and AD by ELISA. Results: The Peptidomic Analysis of the potential comorbidity biomarkers for T2DM and the AD group includes Osteopontin (OPN), Isoform 2 of Histone H2Btype 2-F and Histone H4. These potential comorbidity biomarkers for T2DM and the AD group are significantly increased than normal control group. OPN concentrations are 1.67 (0.13 - 2.63) mmol/L in the normal control group, 3.15 (1.51 - 5.35) mmol/L in the T2DM group, and 7.66 (3.55 - 15.38) mmol/L in the AD group. Histone H4 concentrations in three groups respectively are 0.21 ± 0.036 mmol/L (normal control), 0.21 ± 0.046 mmol/L (T2DM) and 0.21 ± 0.034 mmol/L(AD). Isoforms 2 of Histone H2Btype 2-F are 1.73 (0.12 - 2.60) mmol/L, 4.71 (1.26 - 6.84) mmol/L and 9.30 (0 - 20.8) mmol/Lin three groups respectively. Conclusion: The inflammatory mechanism may lead to an increase of histone content in the urine of AD and T2DM patients. Clinical test of these potential comorbidity biomarkers Histones and Osteopontin would be the diagnosis of comorbidity AD and T2DM.
Limit Circle/Limit Point Criteria for Second-Order Superlinear Differential Equations with a Damping Term
Lihong Xing,Wei Song,Zhengqiang Zhang,Qiyi Xu
Journal of Applied Mathematics , 2012, DOI: 10.1155/2012/361961
Abstract: The purpose of the present paper is to establish some new criteria for the classifications of superlinear differential equations as being of the nonlinear limit circle type or of the nonlinear limit point type. The criteria presented here generalize some known results in literature.
Combining the Physical Adsorption Approach and the Covalent Attachment Method to Prepare a Bifunctional Bioreactor
Mengxing Dong,Zhuofu Wu,Ming Lu,Zhi Wang,Zhengqiang Li
International Journal of Molecular Sciences , 2012, DOI: 10.3390/ijms130911443
Abstract: Aminopropyl-functionalized SBA-15 mesoporous silica was used as a support to adsorb myoglobin. Then, in order to avoid the leakage of adsorbed myoglobin, lysozyme was covalently tethered to the internal and external surface of the mesoporous silica with glutaraldehyde as the coupling agent. The property of amino-functionalized mesoporous silica was characterized by N 2 adsorption-desorption and thermogravimetric (TG) analysis. The feature of the silica-based matrix before and after myoglobin adsorption was identified by fourier transform infrared (FTIR) and UV/VIS measurement. With o-dianisidine and H 2O 2 as the substrate, the peroxidase activity of adsorbed myoglobin was determined. With Micrococus lysodeilicus as the substrate, the antibacterial activity of covalently tethered lysozyme was measured. Results demonstrated that the final product not only presented peroxidase activity of the myoglobin but yielded antibacterial activity of the lysozyme.
Robust Model Reference Adaptive Control Using Matrix Factorization For Multivariable Systems

Xie Xuejun,Zhang Zhengqiang,

系统科学与数学 , 2006,
Abstract: In this paper, for multivariable systems with unmodeled dynamics, the problem of robust direct model reference adaptive control using high frequency gain matrix Kp = LDU factorization is studied, and the stability and robustness of the closed-loop system are analyzed rigorously.
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