Rapid Stress Analytical Solutions of Steel Strips Subjected to Non-uniform Tensile Loads Based on New Symplectic Method

Haijun Yu,Anrui He,Wenquan Sun,Chihuan Yao,Chao Liu 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.5

This paper deals with the stress distribution problem of steel strips subjected to non-uniform tensile loads at both ends, which induce the transverse in-plane compressive stress and is important for researching the transverse buckling of the steel strip. For stress distribution problem, the traditional fi nite element method (FEM) has acceptable accuracy while it takes too long computing time to be applied to on-site production and the semi-inverse analytical method needs to preset the form of stress solution and gets the solution with a certain error. Thence, a rapid symplectic analytical method for solving stress distribution problem of steel strips is presented, which is based on the Hamiltonian system unlike other traditional method based on the Lagrangian system. Furthermore, the rational and rigorous derivation without any forecast about the form of solution makes the stress result have high precision with short computing time. Finally, the symplectic method is demonstrated be more effi cient and suitable in the on-line calculation by comparing with FEM.

Consensus of Multi-agent Systems with Feedforward Nonlinear Dynamics and Digraph

Shuzhen Yu,Haijun Jiang,Zhiyong Yu,Cheng Hu 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.4

This paper considers a high-order consensus problem of multi-agent system with feedforward nonlinear and time-varying input delay in a directed network. In order to achieve the consensus, we propose a low gain distributed protocol which can get rid of impacts of feedforward nonlinearity and an arbitrarily bounded input delay on the consensus problem. Moreover, for any upper bound time-varying delay and strongly connected diagraph, the proposed controller can solve the consensus problem of multi-agent systems with feedforward nonlinearity if the designed parameter q is great than the threshold value. Finally, several numerical simulations are presented to demonstrate the validity of the theoretical results.

Algorithms of Brainstem Auditory Evoked Potential Extraction

Haijun Lin,Xinlei Wang,Jia Yu,Bo Liu 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.10

To extract the brainstem auditory evoked potentials and remove the spontaneous electroencephalograph and other background noises, the paper proposed a new method of wavelet information entropy theory de-noising based on wavelet de-noising. In the method, the threshold function is improved by introducing the weighting factor and determine the weighting factor according to the wavelet information entropy to obtain a better de-noising effect. The simulation experiment shows, compared to the traditional wavelet de-noising method, the new method can preserve the details of the signal better and make the signal waveform smoother. At the same time, the new method can suppress the pulse signal, which make the system has a better de-noising performance and achieve higher quality extraction brainstem auditory evoked potentials.

Leader-following Cluster Consensus in Multi-agent Systems with Intermittence

Da Huang,Haijun Jiang,Zhiyong Yu,Chengjun Kang,Cheng Hu 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.2

In this paper, the cluster consensus problem of first-order nonlinear multi-agent systems with aperiodic intermittent communication is studied through pinning leader-following approach. The pinning consensus algorithm based on the relative local intermittent information is designed according to the varies linking ways of clustered network structure. New notions of leading intermittence and inter-cluster intermittence which related to the intermittent linking ways of leader-following clustered structure are developed, and several new systems with intermittence are established due to the new notions. Besides, dynamics with inherent delay are also considered to extend our results to a more general framework. The original communication graph without intermittent pattern is supposed to be directed and weakly connected. Some consensus criteria are derived to guarantee that the cluster consensus problem for the systems with intermittent communication can be solved. Finally, numerical simulations are given to illustrate the effectiveness of the theoretical results.

Fully Distributed Event-triggered Semi-global Consensus of Multi-agent Systems with Input Saturation and Directed Topology

Siyu Chen,Haijun Jiang,Zhiyong Yu 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.12

This paper studies the consensus problem of multi-agent systems with input saturation and directed communication topology, by utilizing the low-gain feedback method and the event-triggered control laws. Two event-triggered control laws, the centralized and the distributed laws, are proposed to guarantee semi-global consensus of the multi-agent systems. Then, a sufficient condition is presented to prove strictly positive low bound of inner-event time, i.e., the Zeno behavior can be avoided. Finally, the effectiveness of the proposed event-triggered laws is further verified by an example.

Peroxiredoxin System of Aspergillus nidulans Resists Inactivation by High Concentration of Hydrogen Peroxide-Mediated Oxidative Stress

( Yang Xia ),( Haijun Yu ),( Zhemin Zhou ),( Naoki Takaya ),( Shengmin Zhou ),( Ping Wang ) 한국미생물생명공학회(구 한국산업미생물학회) 2018 Journal of microbiology and biotechnology Vol.28 No.1

Most eukaryotic peroxiredoxins (Prxs) are readily inactivated by a high concentration of hydrogen peroxide (H₂O₂) during catalysis owing to their “GGLG” and “YF” motifs. However, such oxidative stress sensitive motifs were not found in the previously identified filamentous fungal Prxs. Additionally, the information on filamentous fungal Prxs is limited and fragmentary. Herein, we cloned and gained insight into Aspergillus nidulans Prx (An.PrxA) in the aspects of protein properties, catalysis characteristics, and especially H₂O₂ tolerability. Our results indicated that An.PrxA belongs to the newly defined family of typical 2-Cys Prxs with a marked characteristic that the “resolving” cysteine (C_R) is invertedly located preceding the “peroxidatic” cysteine (C_P) in amino acid sequences. The inverted arrangement of C_R and C_P can only be found among some yeast, bacterial, and filamentous fungal deduced Prxs. The most surprising characteristic of An.PrxA is its extraordinary ability to resist inactivation by extremely high concentrations of H₂O₂, even that approaching 600 mM. By screening the H₂O₂-inactivation effects on the components of Prx systems, including Trx, Trx reductase (TrxR), and Prx, we ultimately determined that it is the robust filamentous fungal TrxR rather than Trx and Prx that is responsible for the extreme H₂O₂ tolerence of the An.PrxA system. This is the first investigation on the effect of the electron donor partner in the H₂O₂ tolerability of the Prx system.

Cloning and Characterization of Filamentous Fungal S-Nitrosoglutathione Reductase from Aspergillus nidulans

( Yao Zhou ),( Shengmin Zhou ),( Haijun Yu ),( Jingyi Li ),( Yang Xia ),( Baoyi Li ),( Xiaoli Wang ),( Ping Wang ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.5

S-Nitrosoglutathione reductase (GSNOR) metabolizes S-nitrosoglutathione (GSNO) and has been shown to play important roles in regulating cellular signaling and formulating host defense by modulating intracellular nitric oxide levels. The enzyme has been found in bacterial, yeast, mushroom, plant, and mammalian cells. However, to date, there is still no evidence of its occurrence in filamentous fungi. In this study, we cloned and investigated a GSNOR-like enzyme from the filamentous fungus Aspergillus nidulans. The enzyme occurred in native form as a homodimer and exhibited low thermal stability. GSNO was an ideal substrate for the enzyme. The apparent Km and kcat values were 0.55 mM and 34,100 min-1, respectively. Substrate binding sites and catalytic center amino acid residues based on those from known GSNORs were conserved in this enzyme, and the corresponding roles were verified using site-directed mutagenesis. Therefore, we demonstrated the presence of GSNOR in a filamentous fungus for the first time.

Highly Efficient and Recyclable g-C3N4/CuO Hybrid Nanocomposite Towards Enhanced Visible-Light Photocatalytic Performance

Shiquan Hong,Yong Yu,Zhijie Yi,Haijun Zhu,Wencheng Wu,Peiyan Ma 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.11

A highly efficient visible-light-driven g-C3N4/CuO hybrid nanocomposite catalyst with different molar contents of CuO are successfully fabricated via a simple liquid phase synthesis process and applied to the degradation of Rhodamine B (RhB) solution. The results reveal that monodisperse CuO nanoparticles with a size of less than 10 nm are uniformly distributed on the surface of gC3N4 nanosheets. Compared with the pure g-C3N4 and CuO, the as-prepared nanocomposite displays significantly enhanced photocatalytic performance under visible-light irradiation. Attractively, the photocatalytic activities of the nanocomposite catalysts can be tuned by adjusting the molar ratio of g-C3N4 and CuO. When the molar ratio reaches 2:1, the nanocomposite exhibits the highest photocatalytic activity, which can decompose RhB completely in 5 min. The improved performance could be ascribed to the formation of heterostructure between g-C3N4 and CuO as well as the decreased particle size of CuO, the presence of H2O2, large surfaceexposure area and the suitable band position of g-C3N4/CuO nanocomposite. Interestingly, the nanocomposite shows excellent stability and recyclable property toward the photodegradation of RhB. Finally, a possible photocatalytic mechanism is proposed.

Smart and versatile biomaterials for cutaneous wound healing

Minxiong Li,Wenzheng Xia,Yi Min Khoong,Lujia Huang,Xin Huang,Hsin Liang,Yun Zhao,Jiayi Mao,Haijun Yu,Tao Zan 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

The global increase of cutaneous wounds imposes huge health and financial burdens on patients and society. Despite improved wound healing outcomes, conventional wound dressings are far from ideal, owing to the complex healing process. Smart wound dressings, which are sensitive to or interact with changes in wound condition or environment, have been proposed as appealing therapeutic platforms to effectively facilitate wound healing. In this review, the wound healing processes and features of existing biomaterials are firstly introduced, followed by summarizing the mechanisms of smart responsive materials. Afterwards, recent advances and designs in smart and versatile materials of extensive applications for cutaneous wound healing were submarined. Finally, clinical progresses, challenges and future perspectives of the smart wound dressing are discussed. Overall, by mapping the composition and intrinsic structure of smart responsive materials to their individual needs of cutaneous wounds, with particular attention to the responsive mechanisms, this review is promising to advance further progress in designing smart responsive materials for wounds and drive clinical translation.