Scaled Consensus of Disturbed Multi-agent Systems with Output Saturation

Heng Lei,Tao Han,Xi-Sheng Zhan,Jie Wu,Huaicheng Yan 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.10

This paper studies the problem of scaled consensus with output saturation under exogenous disturbances, that is, under exogenous disturbances the state of the agent reaches an assigned proportion, rather than a common value. The main contribution of this work is to propose a new nonlinear protocol, which attenuates the exogenous disturbances by designing a disturbance observer, so that the states of all agents will be proportional to each other. In addition, with the help of integral Lyapunov function, a sufficient condition for the multi-agent system to achieve the scaled consensus with output saturation under exogenous disturbances is obtained under the directed strong connection graph. Finally, a simulation example is given to verify the validity of the results of this work.

Simulation analysis and evaluation of decontamination effect of different abrasive jet process parameters on radioactively contaminated metal

Zhong Lin,Deng Jian,Zuo Zhe-wen,Huang Can-yu,Chen Bo,Lei Lin,Lei Ze-yong,Lei Jie-heng,Zhao Mu,Hua Yun-fei 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.11

A new method of numerical simulating prediction and decontamination effect evaluation for abrasive jet decontamination to radioactively contaminated metal is proposed. Based on the Computational Fluid Dynamics and Discrete Element Model (CFD-DEM) coupled simulation model, the motion patterns and distribution of abrasives can be predicted, and the decontamination effect can be evaluated by image processing and recognition technology. The impact of three key parameters (impact distance, inlet pressure, abrasive mass flow rate) on the decontamination effect is revealed. Moreover, here are experiments of reliability verification to decontamination effect and numerical simulation methods that has been conducted. The results show that: 60Co and other homogeneous solid solution radioactive pollutants can be removed by abrasive jet, and the average removal rate of Co exceeds 80%. It is reliable for the proposed numerical simulation and evaluation method because of the well goodness of fit between predicted value and actual values: The predicted values and actual values of the abrasive distribution diameter are Ф57 and Ф55; the total coverage rate is 26.42% and 23.50%; the average impact velocity is 81.73 m/s and 78.00 m/s. Further analysis shows that the impact distance has a significant impact on the distribution of abrasive particles on the target surface, the coverage rate of the core area increases at first, and then decreases with the increase of the impact distance of the nozzle, which reach a maximum of 14.44% at 300 mm. It is recommended to set the impact distance around 300 mm, because at this time the core area coverage of the abrasive is the largest and the impact velocity is stable at the highest speed of 81.94 m/s. The impact of the nozzle inlet pressure on the decontamination effect mainly affects the impact kinetic energy of the abrasive and has little impact on the distribution. The greater the inlet pressure, the greater the impact kinetic energy, and the stronger the decontamination ability of the abrasive. But in return, the energy consumption is higher, too. For the decontamination of radioactively contaminated metals, it is recommended to set the inlet pressure of the nozzle at around 0.6 MPa. Because most of the Co elements can be removed under this pressure. Increasing the mass and flow of abrasives appropriately can enhance the decontamination effectiveness. The total mass of abrasives per unit decontamination area is suggested to be 50 g because the core area coverage rate of the abrasive is relatively large under this condition; and the nozzle wear extent is acceptable

Cerebellar Schistosomiasis: A Case Report with Clinical Analysis

Heng Wan,Ding Lei,Qing Mao 대한기생충학열대의학회 2009 The Korean Journal of Parasitology Vol.47 No.1

Multi-path Routing Policy for Content Distribution in Content Network

( Lei Yang ),( Chaowei Tang ),( Heng Wang ),( Hui Tang ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.5

Content distribution technology, which routes content to the cache servers, is considered as an effective method to reduce the response time of the user requests. However, due to the exponential increases of content traffic, traditional content routing methods suffer from high delay and consequent inefficient delivery. In this paper, a content selection policy is proposed, which combines the histories of cache hit and cache hit rate to collaboratively determine the content popularity. Specifically, the CGM policy promotes the probability of possible superior paths considering the storage cost and transmission cost of content network. Then, the content routing table is updated with the proportion of the distribution on the paths. Extensive simulation results show that our proposed scheme improves the content routing and outperforms existing routing schemes in terms of Internet traffic and access latency.

Output common mode voltage of a newly combined three‑phase full‑bridge duplex inverter

Hengli Wang,Lei Yuan,Qiang Ren 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.9

Multilevel inverters, owing to their high equivalent switching frequency, high quality of output waveforms, fast dynamic response, and high redundancy, contribute significantly to high-efficiency and high-power inverter applications. However, in practical scenarios, multilevel inverters also have negative impacts. The output common mode voltage is one of the typical problems, which may harm the reliability of systems. In this study, a combined three-phase full-bridge duplex inverter is proposed. Then, the general expression of the proposed inverter’s output common mode voltage is derived based on the numerical double Fourier series. The generation mechanism of the output common mode voltage is subsequently revealed. A common mode voltage suppression strategy, which is universal and applicable to other multiple inverter topologies, is also proposed. The effectiveness of the proposed theory and control strategy is validated through the simulation and the experiment.

Calculation method of residual fatigue life of in-service unbonded flexible pipe

Qinglong Lei,Xiaohua Zhu,Heng Luo 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.5

As a catenary riser, unbonded flexible pipe (UFP) has the advantages of convenient installation, recyclability, flexibility, anti-corrosion and large design space. To analyze the residual fatigue life of in-service unbonded flexible riser (UFR), a global model of riser is established in this paper. By analyzing the distribution of configuration, tension, bending moment and bending curvature along the riser under static and dynamic loads, the most dangerous position and dynamic response are determined. And then, the residual fatigue life of the UFR is calculated. The calculation results show that the fatigue life of the UFR is greatly affected by the pipe annulus condition, and the dry annulus condition is 4.6 times that of the wet annulus condition. It is concluded that when evaluating the remaining fatigue life of an inservice UFR, the S-N curve of the tensile amour layers must be calculated according to different annular conditions, so that the fatigue life can be accurately obtained. Summarily, this paper provides an effective method for calculating the residual fatigue life of in-service UFRs.

Orthosteric and allosteric action of the C5a receptor antagonists

Liu, Heng,Kim, Hee Ryung,Deepak, R. N. V. Krishna,Wang, Lei,Chung, Ka Young,Fan, Hao,Wei, Zhiyi,Zhang, Cheng Nature Publishing Group 2018 Nature Structural and Molecular Biology Vol. No.

Experimental and Numerical Investigation on the Cyclic Behavior of SRC Columns considering Unsymmetrical Confinement Effect

Xianpan Liu,Lei Zeng,Yunfeng Xiao,Yanhua Liu,Heng Zhang,Yun Cao 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.4

Experimental and numerical studies were conducted on the cyclic behavior of steel reinforced concrete (SRC) columns with T-shaped and L-shaped steel section. A total of 8 SRC columns were tested under axial compression and lateral cyclic loading. The design details, loading procedure and main results, including the failure modes, hysteretic characteristics and ductility were reported. Four failure modes as flexural failure, shear bond failure, shear compression failure and shear compound failure were observed. By considering various unsymmetrical confinement and plastic hinge region, the experimental study was supplemented by numerical analysis to study the influence of axial compression ratio, shear-span ratio and concrete strength. The results revealed that the FEA is in good agreement with the experimental results. The ultimate loading of specimen with confinement effect has been improved by 21.4% − 33.8%. The failure modes is dominated by the shear-span ratio and type of cross section. The specimens with smaller shear-span ratio are prone to shear failure, while the unsymmetrical steel arrangement causes shear compound failure which is combined with shear bond failure and shear compression failure. Moreover, the specimens with larger shear-span ratio and stirrup ratio present greater deformation capacity and ductility. In practical engineering, the confinement degree of SRC columns with unsymmetrical steel section can be enhanced by increasing the stirrup ratio and arranging the cross ties.

Effects of exploration and molecular mechanism of CsV on eNOS and vascular endothelial functions

Zuo, Deyu,Jiang, Heng,Yi, Shixiong,Fu, Yang,Xie, Lei,Peng, Qifeng,Liu, Pei,Zhou, Jie,Li, Xunjia Techno-Press 2022 Advances in nano research Vol.12 No.5

This study aimed to investigate the effects and potential mechanisms of Chikusetsusaponin V (CsV) on endothelial nitric oxide synthase (eNOS) and vascular endothelial cell functions. Different concentrations of CsV were added to animal models, bovine aorta endothelial cells (BAECs) and human umbilical vein endothelial cells (HUVECs) cultured in vitro. qPCR, Western blotting (WB), and B ultrasound were performed to explore the effects of CsV on mouse endothelial cell functions, vascular stiffness and cellular eNOS mRNA, protein expression and NO release. Bioinformatics analysis, network pharmacology, molecular docking and protein mass spectrometry analysis were conducted to jointly predict the upstream transcription factors of eNOS. Furthermore, pulldown and ChIP and dual luciferase assays were employed for subsequent verification. At the presence or absence of CsV stimulation, either overexpression or knockdown of purine rich element binding protein A (PURA) was conducted, and PCR assay was employed to detect PURA and eNOS mRNA expressions, Western blot was used to detect PURA and eNOS protein expressions, cell NO release and serum NO levels. Tube formation experiment was conducted to detect the tube forming capability of HUVECs cells. The animal vasodilation function test detected the vasodilation functions. Ultrasonic detection was performed to determine the mouse aortic arch pulse wave velocity to identify aortic stiffness. CsV stimulus on bovine aortic cells revealed that CsV could upregulate eNOS protein levels in vascular endothelial cells in a concentration and time dependent manner. The expression levels of eNOS mRNA and phosphorylation sites Ser1177, Ser633 and Thr495 increased significantly after CsV stimulation. Meanwhile, CsV could also enhance the tube forming capability of HUVECs cells. Following the mice were gavaged using CsV, the eNOS protein level of mouse aortic endothelial cells was upregulated in a concentration- and time-dependent manner, and serum NO release and vasodilation ability were simultaneously elevated whereas arterial stiffness was alleviated. The pulldown, ChIP and dual luciferase assays demonstrated that PURA could bind to the eNOS promoter and facilitate the transcription of eNOS. Under the conditions of presence or absence of CsV stimulation, overexpression or knockdown of PURA indicated that the effect of CsV on vascular endothelial function and eNOS was weakened following PURA gene silence, whereas overexpression of PURA gene could enhance the effect of CsV upregulating eNOS expression. CsV could promote NO release from endothelial cells by upregulating the expression of PURA/eNOS pathway, improve endothelial cell functions, enhance vasodilation capability, and alleviate vessel stiffness. The present study plays a role in offering a theoretical basis for the development and application of CsV in vascular function improvement, and it also provides a more comprehensive understanding of the pharmacodynamics of CsV.

ST6GALNAC1 promotes the invasion and migration of breast cancer cells via the EMT pathway

Luo Yunzhao,Cao Heng,Lei Chuqi,Liu Jun 한국유전학회 2023 Genes & Genomics Vol.45 No.11

Background A specific sialyl-transferases called ST6GALNAC1 has been proven to up-regulate abnormal O‐glycosylation, which is strongly associated with tumorigenesis and cancer progression. However, the precise pathological outcome of ST6GALNAC1 expression in breast cancer cells remains unknown. Therefore, our study aims to investigate the functional role of ST6GALNAC1 and its impact on the epithelial-mesenchymal transition (EMT) pathway in breast cancer cells. Methods Plasmids with siRNA were used to construct ST6GALNAC1 knockoff (si-ST6GALNAC1) MDA-MB-231 and MDA-MB-453 cells, while lentiviruses were used to construct ST6GALNAC1 over-expression (oe-ST6GALNAC1) MCF-7 and BT474 cells. Transfer efficiency was verified by Western Blot. Then we selected transfected cells and assessed the changes in cell proliferation, invasion, migration, and EMT markers. Results The expression of ST6GALNAC1 significantly enhanced cell migration and invasion, which was confirmed by Wound Scratch Assay and Transwell Assay. Particularly, ST6GALNAC1 expression directly induced the EMT signaling pathway. E-cadherin was markedly decreased in oe-ST6GALNAC1 cells, accompanied by an up-regulation of mesenchymal markers including N-cadherin, snail, and ZEB1. However, no significant correlation was found between ST6GALNAC1 expression and cell proliferation. All of the outcomes were reversely validated in si-ST6GALNAC1 cells. Conclusions The expression of ST6GALNAC1 promotes cell migration and invasion probably by triggering the molecular process of the EMT pathway in breast cancer cells, which may provide new clues for designing novel molecular targeted drugs in breast cancer treatment.