Improved Cascade Control System for a Class of Unstable Processes with Time Delay

Cheng-qiang Yin,Hong-tao Wang,Qun Sun,Ling Zhao 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.1

An improved cascade control scheme is proposed based on modified Smith predictor for controllinga class of unstable processes with time delay. The proposed control structure consist three controllers of whichthe secondary loop has one controller and the primary loop has two controllers. The secondary loop controller isdesigned according to Internal Model Control (IMC) principles. The primary loop set point tracking controller anddisturbance rejection controller are designed using the same procedure based on modified Smith predictor controlstructure. An analytical method on the basis of the Internal Model Control design principle is adopted for the twocontrollers which reduces complexity in design. The two controllers in primary loop are designed as proportional,integral and derivative (PID) controller cascaded with a lead-lag filter. Moreover, suitable values are recommendedfor the three controllers based on extensive simulations. Simulations studies are carried out to demonstrate theeffectiveness of the proposed method.

K-doping effect of the superconductivity in K2xFeTe1-xSx (0.07 ≤ x ≤ 0.3)

Cheng Cheng,Zhenjie Feng,Qing Li,Tao Li,Qiang Hou,Fei Chen,Zhongmin Ou,Jun-Yi Ge,Shixun Cao,Jincang Zhang 한국물리학회 2019 Current Applied Physics Vol.19 No.4

Bulk samples of K doping K2xFeTe1-xSx with x=0.07, 0.1, 0.2, 0.3 are successfully prepared by using easy-to-use stable compound K2S as the reactant. The lattice constant calculated from X-ray diffraction patterns indicate that K ions enter the Fe-Te-S layers. K doping is beneficial enhance the superconductivity transition temperature from the R-T curves. The apparent diamagnetic signal is observed in M-T curves when the content of K is smaller than 0.1. However, differential curves (dM/dT) in K-rich samples appear sharp slope mutations, which means that the Meissner effect signal is covered by the increased excess ferromagnetic ions. The number of excess Fe magnetic ions is proportional to K content, which may play an important role in determining the superconductivity.

A structure-based approach to evaluation product adaptability in adaptable design

Qiang Cheng,Guojun Zhang,Zhifeng Liu,Peihua Gu,Ligang Cai 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.5

Adaptable design, as a new design paradigm, involves creating designs and products that can be easily changed to satisfy different requirements. In this paper, two types of product adaptability are proposed as essential adaptability and behavioral adaptability, and through measuring which respectively a model for product adaptability evaluation is developed. The essential adaptability evaluation proceeds with analyzing the independencies of function requirements and function modules firstly based on axiomatic design, and measuring the adaptability of interfaces secondly with three indices. The behavioral adaptability reflected by the performance of adaptable requirements after adaptation is measured based on Kano model. At last, the effectiveness of the proposed method is demonstrated by an illustrative example of the motherboard of a personal computer. The results show that the method can evaluate and reveal the adaptability of a product in essence, and is of directive significance to improving design and innovative design.

A simple approach to the elasto-plastic coupling analyses of circular tunnels in confining pressure-dependent strain-softening rock masses

Qiang Zhang,Cheng Li,Qiang Guo,Ming Min,Yanning Wang,Binsong Jiang 한국자원공학회 2017 Geosystem engineering Vol.20 No.5

The conventional strain-softening behaviors which assume the strength parameters as the functions of the plastic strain have been studied using various methods. However, rock-like materials have also been found to manifest pressure-dependent behavior for both elastic and plastic rock masses. The realization of the radial stress was found to be continuous, and gradually increased from supporting stress to in situ stress for the circular openings under hydrostatic pressure. The radial stress was spaced as numbers of sections, and each annulus was considered as an ideal plastic rock mass. The close-formed analytical solutions of each annulus can be easily obtained. Therefore, using the displacement continuum and stress boundary conditions, the dimensionless radius corresponding to the spaced radius could be derived. The radial stress and plastic shear strain at the inner radius of the outer adjacent annulus were employed to describe the material property evolution law. Then, the radii could be recursively obtained. Finally, for the conventional strain-softening rock masses, the pressure-dependent elastic rock and elasto-plastic coupling strain-softening rock masses were employed to validate the proposed approach. In this study, having completed the above steps, it was concluded that the results were in accordance with the numerical methods.

Research on Common Mode Interference of PWM Inverter Driving System

CHENG Qiang,DU Zhong-Min 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.5

In order to suppress electromagnetic interference of PWM driving system, electromagnetic interference characteristics ,system distribution and main influence factor in this system must be accurately mastered. Therefore this paper used conduction separation network to meter common mode interference of PWM inverter system ,and through comparison results of different conditions ,the author obtained the distribution of common mode interference on power side and load side . Then the team made analysis and improvement to the common-mode interference model, at last through theory analysis and calculation some suppression method to CM interference was found , which may provide certain theoretical guidance for EMI filter design.

FEM analysis of the modular prefabricated steel-concrete composite beam-column internal joint under reciprocating action

Cheng Long Wu,Jian Cheng Kan,Qi Hui Wang,Ji Ming Liu,Zun Qiang Li 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.41 No.1

Prefabricated steel-concrete composite structure has the advantages of large bearing capacity, reliable connection, and good durability, which is of great significance to the development of building industrialization. In this paper, a finite element model (FEM) of the modular prefabricated SRC column-steel beam composite joint is established and verified its accuracy through ABAQUS. The effects of various parameter variables on the hysteresis curve, skeleton curve, ductility, energy consumption, and performance deterioration are investigated. The results show that as the axial compression ratio increases, the joint bearing capacity first increases and then decreases, the strength and stiffness have relatively stable degradation characteristics. However, the hysteresis curve has a certain “pinch” phenomenon, which reduces the energy consumption performance. Different column end bolts margin and apertures have little effect on the bearing capacity, strength and stiffness degradation performance, but affect energy consumption and ductility. The width-to-thickness ratio of the square steel tube has a greater impact on the bearing capacity, energy consumption and ductility, and has less impact on the strength and stiffness degradation performance. As the thickness of the joint cover plate increases, the bearing capacity, energy consumption and initial stiffness of the joint gradually increase, the ductility first increases and then decreases.

Personal Safety in Electromagnetic Environment of Electric Vehicle

Cheng Qiang,Du Zhong-min 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.6

With the extensive application of automotive electrical and electronic equipment, issues of electromagnetic radiation and electromagnetic compatibility have become increasingly prominent, human body in complex automotive electromagnetic environment is bound to be some damage of electromagnetic radiation. This paper established a relatively sophisticated car simulation model,through electromagnetic characteristics of antenna model, we got automotive electric field distribution and simulation results of human body SAR value, so conclusion can be drawn that automotive electromagnetic environment is relatively safe to passengers.

Relationship Between PTEN and Livin Expression and Malignancy of Renal Cell Carcinomas

Cheng, Tao,Zhang, Jian-Guo,Cheng, Yuan-He,Gao, Zhong-Wei,Ren, Xiao-Qiang Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.6

Objectives: This study focused on PTEN and Livin expression and associations with malignancy in human renal clear cell carcinomas (RCCC). Methods: PTEN and Livin expression was assessed in 100 RCCC tissue samples, 50 paracarcinoma cases, and 20 normal renal tissue samples using the immunohistochemical Streptavidin proxidase (SP) method. The relationships between binding and corresponding biological characteristics, such as histological grade, lymph node metastases, and clinical stages were analyzed. Results: Positive PTEN expression in RCCC was significantly lower than in renal tissue adjacent to carcinoma tissue and normal renal tissue (P<0.01). Livin expression in the renal tissue adjacent to the carcinoma and normal renal tissues exhibited only low levels, whereas overall Livin expression in RCCC was statistically significant (P<0.01). In RCCC, PTEN expression rate gradually decreased with an increase in clinical stage, whereas that of Livin increased to statistically significant levels (P<0.01), PTEN and Livin levels being negatively correlated (r=-0.395, P<0.01). Conclusions: PTEN and Livin are important in RCCC development. The two factors combined are expected to provide indices for estimating RCCC malignancy and progression levels, as well as references for RCCC diagnosis and treatment.

Development and Evaluation of Loop-Mediated Isothermal Amplification Assay for Rapid Detection of Tylenchulus semipenetrans Using DNA Extracted from Soil

Zhi-Qiang Song,Ju-E Cheng,Fei-Xue Cheng,De-Yong Zhang,Yong Liu 한국식물병리학회 2017 Plant Pathology Journal Vol.33 No.2

Tylenchulus semipenetrans is an important and widespreadplant-parasitic nematode of citrus worldwideand can cause citrus slow decline disease leading tosignificant reduction in tree growth and yield. Rapidand accurate detection of T. semipenetrans in soil isimportant for the disease forecasting and management. In this study, a loop-mediated isothermal amplification(LAMP) assay was developed to detect T. semipenetrans using DNA extracted from soil. A setof five primers was designed from the internal transcribedspacer region (ITS1) of rDNA, and was highlyspecific to T. semipenetrans. The LAMP reaction wasperformed at 63°C for 60 min. The LAMP productwas visualized directly in one reaction tube by addingSYBR Green I. The detection limit of the LAMP assaywas 10–2 J2/0.5 g of soil, which was 10 times moresensitive than conventional PCR (10–1 J2/0.5 g of soil). Examination of 24 field soil samples revealed that theLAMP assay was applicable to a range of soils infestednaturally with T. semipenetrans, and the total assaytime was less than 2.5 h. These results indicated thatthe developed LAMP assay is a simple, rapid, sensitive,specific and accurate technique for detection of T. semipenetrans in field soil, and contributes to the effectivemanagement of citrus slow decline disease.

Evaluations of load-deformation behavior of soil nail using hyperbolic pullout model

Zhang, Cheng-Cheng,Xu, Qiang,Zhu, Hong-Hu,Shi, Bin,Yin, Jian-Hua Techno-Press 2014 Geomechanics & engineering Vol.6 No.3

Soil nailing, as an effective stabilizing method for slopes and excavations, has been widely used worldwide. However, the interaction mechanism of a soil nail and the surrounding soil and its influential factors are not well understood. A pullout model using a hyperbolic shear stress-shear strain relationship is proposed to describe the load-deformation behavior of a cement grouted soil nail. Numerical analysis has been conducted to solve the governing equation and the distribution of tensile force along the nail length is investigated through a parametric study. The simulation results are highly consistent with laboratory soil nail pullout test results in the literature, indicating that the proposed model is efficient and accurate. Furthermore, the effects of key parameters, including normal stress, degree of saturation of soil, and surface roughness of soil nail, on the model parameters are studied in detail.