New Method of Designing Controller for Uncertain Diff erential-Diff erence Systems and Application to Time-Delay Operational Amplifi er System

Ke Jian,Chung-Cheng Chen,Yen-Ting Chen,Gui-hong Lin 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.6

This study combines the feedback linearization method and our recent researches of Chen electrical unifying approach to propose a global tracking controller design for nonlinear uncertain diff erential-diff erence systems with time delay. One example, which cannot be solved by the fi rst paper on the almost disturbance decoupling problem, is presented in this study to show the essential points that the tracking performance is easily solved by the proposed approach. The study applies Chen electrical unifying approach to take the place of using the disorganized virtual ground technique and the Kirchhoff ’s law for those traditional approaches. In order to show its signifi cant practicability, the study has fi rstly designed an easy-to-implement adder and a time-delay circuit, and an unstable time-delay operational amplifi er control system based on the Chen electrical unifying approach, and then has proposed a stable controller.

Interactions of xanthate with pyrite and galena surfaces in the presence and absence of oxygen

Jian-Hua Chen,Yu-Qiong Li,Li-Hong Lan,Jin Guo 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.1

In this study, first-principles calculations were performed to investigate the interactions of hydrogenxanthate (HOCS₂-) with pyrite (1 0 0) and galena (1 0 0) surfaces. The calculation results suggest thatstrong chemisorption of HOCS₂- occurs at Fe sites on the pyrite (1 0 0) surface, whereas its interaction atPb sites on the galena (1 0 0) surface is weak. The interaction of xanthate with oxidized pyrite surface isweakened while the interaction of xanthate with oxidized galena surface is enhanced. The hydration ofxanthate and mineral surfaces is discussed. Dixanthogen could be formed on the pyrite surface but noton the galena surface.

Expression Analysis of miRNAs in Porcine Fetal Skeletal Muscle on Days 65 and 90 of Gestation

Chen, Jian-hai,Wei, Wen-Juan,Xiao, Xiao,Zhu, Meng-Jin,Fan, Bin,Zhao, Shu-Hong Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.7

MiRNAs (microRNAs) are a class of small non-coding RNA molecules of ~21 nucleotides that down- regulate the expression of target genes at post-transcriptional level. In this study, we first accomplished a preliminary scan of miRNA expression using 65 and 90 day fetal pig skeletal muscle samples by microarray hybridization, and 34 miRNAs showed strong positive signals. Five of these miRNAs were selected for further investigation by real-time RT-PCR. The statistical analyses indicated that three miRNAs exhibited significant differential expression (p<0.05) during porcine muscle development from 65 to 90 days of gestation, e.g., miR-24 and miR-424 were down-regulated while miR-133a was up-regulated. Multi-tissue RT-PCR was performed to detect the expression patterns of the five miRNA precursors. The results showed that most of these precursor miRNAs were ubiquitously expressed in different porcine tissues.

Tristetraprolin Overexpression in Gastric Cancer Cells Suppresses PD-L1 Expression and Inhibits Tumor Progression by Enhancing Antitumor Immunity

Jian Guo,Huiheng Qu,Ting Shan,Yigang Chen,Ye Chen,Jiazeng Xia 한국분자세포생물학회 2018 Molecules and cells Vol.41 No.7

The RNA-binding protein tristetraprolin (TTP) binds to adenosine- uridine AU-rich elements in the 3’-untranslated region of messenger RNAs and facilitates rapid degradation of the target mRNAs. Therefore, it regulates the expression of multiple cancer and immunity-associated transcripts. Furthermore, a lack of TTP in cancer cells influences cancer progression and predicts poor survival. Although the functions of TTP on cancer cells have previously been researched, the mechanism of TTP on the interaction between cancer cells with their microenvironment remains undiscovered. In this study, we admed to determine the role of cancer cell TTP during the interaction between tumor and immune cells, specifically regulatory T cells (Tregs). We evaluate the capability of TTP to modulate the antitumor immunity of GC and explored the underlying mechanism. The overexpression of TTP in GC cells dramatically increased peripheral blood mononuclear lymphocyte (PBML) -mediated cytotoxicity against GC cells. Increased cytotoxicity against TTP-overexpressed GC cells by PBMLs was determined by Treg development and infiltration. Surprisingly, we found the stabilization of programmed death-ligand 1 (PD-L1) mRNA was declining while TTP was elevated. The PDL1 protein level was reduced in TTP-abundant GC cells. PD-L1 gas been found to play a pivotal role in Treg development and functional maintenance in immune system. Taken together, our results suggest the overexpression of TTP in GC cells not only affects cell survival and apoptosis but also increases PBMLs -mediated cytotoxicity against GC cells to decelerate tumor progression. Moreover, we identified PD-L1 as a critical TTP-regulated factor that contributes to inhibiting antitumor immunity.

Shape-Controlled Synthesis of Melamine Based Polyamide Materials and Application in Suzuki-Miyaura Coupling Reaction

Jian Chen,Yan Zhang,Tao Li,Dajian Zhu 한국고분자학회 2019 Macromolecular Research Vol.27 No.9

The shape of the supporters would influence the catalytic performance in Suzuki-Miyaura coupling reaction. To test the hypothesis, this study synthesized polyamides and their corresponding catalysts with different shapes by the templateassisted method using cheap and commercially available melamine and p-phthalic acid as raw materials. The samples were characterized by SEM, XPS, TEM, XRD, FT-IR, TGA and BET surface area and porosity analyzers. After detailed investigation of these polyamides with different shapes and their applications to catalytic reactions, it was established that these polyamides could be recyclable and efficient catalyst supporters towards Suzuki-Miyaura reactions. Supporters’ shape influence the TOF (turnover frequency) value of the catalysts in Suzuki-Miyaura reaction and interaction between Pd active specie and supporters in the heterogeneous catalysts. Polyamides supported Pd catalysts exhibit excellent activity, selectivity and reusability in water medium.

SECTION 7 : ETHICS AND TECHNOLOGY IN SYSTEMS SCIENCES ; A Framework of Integrating Intelligent Support System for Macro - Economic Forecasting and Pre - monitoring

(Jian Chen) 한국체계과학회 1997 SYSTEM THINKING GLOBALIZATION OF KNOWLEDGE AND COM Vol.- No.-

Analysis and Control of NPC-3L Inverter Fed Dual Three-Phase PMSM Drives Considering their Asymmetric Factors

Chen, Jian,Wang, Zheng,Wang, Yibo,Cheng, Ming The Korean Institute of Power Electronics 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.6

The purpose of this paper is to study a high-performance control scheme for neutral-point-clamping three-level (NPC-3L) inverter fed dual three-phase permanent magnet synchronous motor (PMSM) drives by considering some asymmetric factors such as the non-identical parameters in phase windings. To implement this, the system model is analyzed for dual three-phase PMSM drives with asymmetric factors based on the vector space decomposition (VSD) principle. Based on the equivalent circuits, PI controllers with feedforward compensation are used in the d-q subspace for regulating torque, where the cut-off frequency of the PI controllers are set at the twice the fundamental frequency for compensating both the additional DC component and the second order component caused by asymmetry. Meanwhile, proportional resonant (PR) controllers are proposed in the x-y subspace for suppressing the possible unbalanced currents in the phase windings. A dual three-phase space vector modulation (DT-SVM) is designed for the drive, and the balancing factor is designed based on the numerical fitting surface for balancing the DC link capacitor voltages. Experimental results are given to demonstrate the validity of the theoretical analysis and the proposed control scheme.

Algorithm of Gaussian Sum Filter Based on SGQF for Nonlinear Non-Gaussian Models

Chen Qian,Chengying Song,Sheng Li,Qingwei Chen,Jian Guo 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.8

To improve the filtering effect of the sparse grid quadrature filter (SGQF) under non-Gaussian conditions, the Gaussian sum technique is introduced, and the Gaussian sum sparse grid quadrature filter (GSSGQF) is developed. We present a systematic formulation of the SGQF and extend it to the discrete-time nonlinear system with the non-Gaussian noise. The proposed algorithm approximates the non-Gaussian probability densities by a finite number of weighted sums of Gaussian densities, and takes the SGQF as the Gaussian sub-filter to conduct the timeand measurement update for each Gaussian component. An application in the discrete-time nonlinear system with the non-Gaussian noise has been shown to demonstrate the accuracy of the GSSGQF. It outperforms the unscented Kalman filter (UKF), the cubature Kalman filter (CKF) and the SGQF. Theoretical analysis and simulation results prove that the GSSGQF provides significant performance improvement in the calculation accuracy for nonlinear non-Gaussian filtering problems.

An Interleaved Five-level Boost Converter with Voltage-Balance Control

Chen, Jianfei,Hou, Shiying,Deng, Fujin,Chen, Zhe,Li, Jian The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.5

This paper proposes an interleaved five-level boost converter based on a switched-capacitor network. The operating principle of the converter under the CCM mode is analyzed. A high voltage gain, low component stress, small input current ripple, and self-balancing function for the capacitor voltages in the switched-capacitor networks are achieved. In addition, a three-loop control strategy including an outer voltage loop, an inner current loop and a voltage-balance loop has been researched to achieve good performances and voltage-balance effect. An experimental study has been done to verify the correctness and feasibility of the proposed converter and control strategy.

Experimental study on cold-formed lipped channel stub columns reinforced by steel bars or steel strips

Jian-Feng Chen,Ming-Qi Chen,Yong-Kang Shen,Jian-Hua Shao,Xin-Xin Yang 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.40 No.3

In this paper, the axial compressive properties of cold-formed steel lipped channel stub columns strengthened by rebars or steel strips are experimentally studied. The experiment included two sections. A kind of columns with local buckling is reinforced longitudinally by steel strips at the web. The other is the columns with distorted buckling, which is reinforced longitudinally by steel bars at the curling edge. The failure mode, deformation characteristics, ultimate bearing capacity and load displacement curve of the specimen are obtained through the experiment. On the basis of the experiment, the calculation results of theoretical axial bearing capacity of cold-formed steel lipped channel stub columns in Chinese, North American and Australian code are compared and analyzed. Research indicates: First, the cold-formed steel lipped channel stub columns strengthened by steel bars or steel strips can effectively improve the compressive bearing capacity of the specimen. Secondly, when the initial stress ratio of specimen is less than 0.3, the reinforcement effect is ideal. Thirdly, the three standards don’t stipulate the calculation of theoretical bearing capacity of the specimen strengthened after loading, so there is a large deviation between the theoretical calculation value and the test value.