Locating and identifying model-free structural nonlinearities and systems using incomplete measured structural responses

Lijun Liu,Ying Lei,Mingyu He 국제구조공학회 2015 Smart Structures and Systems, An International Jou Vol.15 No.2

Structural nonlinearity is a common phenomenon encountered in engineering structures under severe dynamic loading. It is necessary to localize and identify structural nonlinearities using structural dynamic measurements for damage detection and performance evaluation of structures. However, identification of nonlinear structural systems is a difficult task, especially when proper mathematical models for structural nonlinear behaviors are not available. In prior studies on nonparametric identification of nonlinear structures, the locations of structural nonlinearities are usually assumed known and all structural responses are measured. In this paper, an identification algorithm is proposed for locating and identifying model-free structural nonlinearities and systems using incomplete measurements of structural responses. First, equivalent linear structural systems are established and identified by the extended Kalman filter (EKF). The locations of structural nonlinearities are identified. Then, the model-free structural nonlinear restoring forces are approximated by power series polynomial models. The unscented Kalman filter (UKF) is utilized to identify structural nonlinear restoring forces and structural systems. Both numerical simulation examples and experimental test of a multi-story shear building with a MR damper are used to validate the proposed algorithm.

Preparation of Polyvinylpyrrolidone-Stabilized Fe0 Nanoparticles for Remediation of Cr(vi)-Spiked Soil

Lijun Yan,Chen He,Xuefeng Hu,Kokyo Oh 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Enhanced bone regeneration using poly(trimethylene carbonate)/ vancomycin hydrochloride porous microsphere scaffolds in presence of the silane coupling agent modified hydroxyapatite nanoparticles

Jian He,Xulin Hu,Luyao Xing,Dongliang Chen,Lijun Peng,Gaofeng Liang,Chengdong Xiong,Xiangchun Zhang,Lifang Zhang 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.99 No.-

Tissue-engineered scaffolds acted as active natural extracellular matrices that allowed for cellattachment, migration, proliferation, and differentiation. To enhance the drug loading, degradationcontrol, and mechanical features of tissue-engineered scaffolds used in bone regeneration applications,we synthesized novel poly(trimethylene carbonate) (PTMC)/modified HA nanoparticles (KHA NPs,modified by silane coupling agent)/vancomycin hydrochloride (VH) porous microspheres scaffold. Thefabricated PTMC/KHA/VH scaffold has unique surface corrosion degradation, excellent surface properties,and high cytocompatibility. The novel PTMC/KHA/VH scaffold was characterized by 42% porosity,100 mmpore size, and 208.2 MPa compressive modulus. After the treatment of a rat femur defect for 4, 8, and 12weeks, the surface corrosion biodegraded of the PTMC/KHA/VH scaffold remarkably decreasedinflammation response and promoted bone regeneration, suggesting its use as a bioactive structurein bone tissue engineering.

Locating and identifying model-free structural nonlinearities and systems using incomplete measured structural responses

Liu, Lijun,Lei, Ying,He, Mingyu Techno-Press 2015 Smart Structures and Systems, An International Jou Vol.15 No.2

Structural nonlinearity is a common phenomenon encountered in engineering structures under severe dynamic loading. It is necessary to localize and identify structural nonlinearities using structural dynamic measurements for damage detection and performance evaluation of structures. However, identification of nonlinear structural systems is a difficult task, especially when proper mathematical models for structural nonlinear behaviors are not available. In prior studies on nonparametric identification of nonlinear structures, the locations of structural nonlinearities are usually assumed known and all structural responses are measured. In this paper, an identification algorithm is proposed for locating and identifying model-free structural nonlinearities and systems using incomplete measurements of structural responses. First, equivalent linear structural systems are established and identified by the extended Kalman filter (EKF). The locations of structural nonlinearities are identified. Then, the model-free structural nonlinear restoring forces are approximated by power series polynomial models. The unscented Kalman filter (UKF) is utilized to identify structural nonlinear restoring forces and structural systems. Both numerical simulation examples and experimental test of a multi-story shear building with a MR damper are used to validate the proposed algorithm.

Chirality detection of amino acid enantiomers by organic electrochemical transistor

Zhang, Lijun,Wang, Guiheng,Xiong, Can,Zheng, Lei,He, Jianbo,Ding, Yunsheng,Lu, Hongbo,Zhang, Guobing,Cho, Kilwon,Qiu, Longzhen Elsevier 2018 Biosensors & bioelectronics Vol.105 No.-

<P><B>Abstract</B></P> <P>Chiral recognition of α-amino acids is attracting increasing interest due to the importance of α-amino acids in protein metabolism as well as in food products and pharmaceuticals. Organic electrochemical transistors (OECTs) with gate electrodes modified with molecularly imprinted polymer (MIP) films were fabricated and successfully used as highly selective and sensitive chiral recognition biosensors for <SMALL>D/L</SMALL>-tryptophan (<SMALL>D</SMALL> <SMALL>/</SMALL> <SMALL>L</SMALL>-Trp) and <SMALL>D/L</SMALL>-tyrosine (<SMALL>D</SMALL> <SMALL>/</SMALL> <SMALL>L</SMALL>-Tyr). The MIP films, which can specifically recognize and has an electrocatalytic effect on the oxidation of Trp and Tyr, together with the amplification function of an OECT, provide a highly sensitive and selective OECT biosensor. The sensor showed a linear response range for <SMALL>L</SMALL>-Trp and <SMALL>L</SMALL>-Tyr from 300 nM to 10 μM with a sensitivity of 3.19 and 3.64 μA/μM, respectivity. And the detection limit for <SMALL>L</SMALL>-Trp and <SMALL>L</SMALL>-Tyr is of 2 nM and 30 nM (S/N > 3). The selectivity factors of <SMALL>L</SMALL>-Trp, <SMALL>D</SMALL>-Trp, <SMALL>L</SMALL>-Tyr and <SMALL>D</SMALL>-Tyr to their enantiomers are 11.6, 3.5, 14.5 and 2.6, respectively. This method can pave the way for widespread applications of OECT-based sensors in chiral material identification.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An novel chiral recognition MIP-OECT sensor was developed. </LI> <LI> The MIP films showed good performance of selective and electro-catalytic oxidation for Trp and Tyr. </LI> <LI> The MIP films together with the amplification function of an OECT afforded a highly sensitive, selective sensor for chirality detection of amino acid enantiomers. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Enhanced Distance Dynamics Model for Community Detection via Ego-Leader

( Cai Lijun ),( Zhang Jing ),( Chen Lei ),( He Tingqin ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.5

Distance dynamics model is an excellent model for uncovering the community structure of a complex network. However, the model has poor robustness. To improve the robustness, we design an enhanced distance dynamics model based on Ego-Leader and propose a corresponding community detection algorithm, called E-Attractor. The main contributions of E-Attractor are as follows. First, to get rid of sensitive parameter λ, Ego-Leader is introduced into the distance dynamics model to determine the influence of an exclusive neighbor on the distance. Second, based on top-k Ego-Leader, we design an enhanced distance dynamics model. In contrast to the traditional model, enhanced model has better robustness for all networks. Extensive experiments show that E-Attractor has good performance relative to several state-of-the-art algorithms.

K-Hop Community Search Based On Local Distance Dynamics

( Tao Meng ),( Lijun Cai ),( Tingqin He ),( Lei Chen ),( Ziyun Deng ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.7

Community search aims at finding a meaningful community that contains the query node and also maximizes (minimizes) a goodness metric. This problem has recently drawn intense research interest. However, most metric-based algorithms tend to include irrelevant subgraphs in the identified community. Apart from the user-defined metric algorithm, how can we search the natural community that the query node belongs to? In this paper, we propose a novel community search algorithm based on the concept of the k-hop and local distance dynamics model, which can naturally capture a community that contains the query node. The basic idea is to envision the nodes that k-hop away from the query node as an adaptive local dynamical system, where each node only interacts with its local topological structure. Relying on a proposed local distance dynamics model, the distances among nodes change over time, where the nodes sharing the same community with the query node tend to gradually move together, while other nodes stay far away from each other. Such interplay eventually leads to a steady distribution of distances, and a meaningful community is naturally found. Extensive experiments show that our community search algorithm has good performance relative to several state-of-the-art algorithms.

Dibenzothiophene hydrodesulfurization over MoP/SiO2 catalyst prepared with sol-gel method

Shuwen Gong,Lijun Liu,Haifeng He,Qingxin Cui 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.5

Silica-supported molybdenum phosphide, MoP/SiO2 catalysts with different Mo weight loadings were prepared by temperature programmed reduction of the oxidic catalyst precursors, which were prepared via sol-gel technique using ethyl silicate-40 as silica source. Samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), BET surface area measurements, and their catalytic activity in hydrodesulfurization (HDS)was tested with dibenzothiophene (DBT) as model compound. XRD analysis revealed the amorphous nature of the catalyst up to 10 wt% Mo loading and the formation of crystalline MoP phase on amorphous silica support with higher Mo loading. BET surface area showed high surface area for catalysts prepared by sol-gel technique with lower Mo content, and the surface area decreased with increasing in Mo loading. The HDS results showed that prepared MoP/SiO2 exhibited high HDS activity and stability toward the catalytic test. Among the series of catalysts prepared, MoP/SiO2 containing 20 wt% Mo was found to be the most active catalyst. And the effects of reaction temperature and hydrogen pressure on conversion and product selectivity were investigated.

Matching Algorithm Based on Semantic Similarity of Service Requirement Ontology for CAE Simulation in Cloud Platform

Ziyun Deng,Jing Zhang,Lijun Cai,Lei Chen,Tingqin He 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.9

When Cloud Platform for Computer Aided Engineering Simulation (CPCAES) are developed to use Service-Oriented Architecture (SOA), on the one hand, it’s necessary to accurately express the service requirements of users, on the other hand it’s need to semantic of the existing services in the platform, and then to match the ontologies. The existing Ontology Web Language for Services / Universal Description Discovery and Integration (OWL-S / UDDI) algorithm has weak matching precision, and not meet the Computer Aided Engineering (CAE) simulation applications. The other semantic similarity algorithms also have weakness in judgment factor, or do not meet the requirements of CAE simulation applications for matching to service requirement ontology in cloud platform. Such that, the authors present a kind of ontology of service requirement for CAE simulation, model the content of the ontology, including resource requirements, computing requirements, computing job requirements, input, output, etc. The authors give the ontology mapping relationship between Ontology Web Language for Services (OWL-S) and the ontology, give the matching decision rules for the ontologies, propose a matching algorithm for matching the ontologies, and compare with the classic OWL-S / UDDI matching algorithm and a similarity matching algorithm proposed in other paper in the ability for measure the similarity quantity of services, the ability to suit the applications, as well as algorithms recall rate and precision rate. The results show the matching algorithm proposed in this paper is more suitable for service requirement ontology of CPCAES, can use the quantify value for the similarity analysis to the ontologies, and has higher precision rate and higher recall rate, which can reach about 90%. The research work in this paper is used in the second prototype of CPCAES, and the research team is developing the third prototype based on semantic Web Services and SOA framework.

Surface Molecularly Imprinted Polymers Based on NH2-MIL-53 for Selective Extraction Ochratoxin A in Real Sample

Xing Zhang,Juan He,Huige Wang,Pengfei Xu,Mingyu Wang,Yuanyuan Li,Jing Chen,Lijun He 한국고분자학회 2022 Macromolecular Research Vol.30 No.10

In this study, surface molecularly imprinted polymers were synthesized with the metal-organic framework NH2-MIL-53 as carrier and naringenin as alternative template of Ochratoxin A (OTA). The amino groups on the surface of NH2-MIL- 53 reacted with the epoxy groups in glycidyl methacrylate (GMA). Subsequently, the double bonds of the GMA grafting on the surface of the material were used for polymerization to prepare the surface molecularly imprinted polymers. The obtained polymers were characterized by scanning electron microscope, transmission electron microscope, energy spectrometer, Fourier infrared spectrometer, X-ray diffraction, and laser particle size analyzer. Synthetic polymer was combined with solid phase extraction for separation and enrichment of trace OTA in grains. The spiked recoveries were found to be 78.95-106.45%, with relative standard deviations ranging from 5.16% to 6.31%. The detection limit and the quantification limit of the method were 0.04 μg·kg-1 and 0.12 μg·kg-1, respectively. Comparing the pretreatment effects of the self-made cartridge and the immunoaffinity column on the OTA in the sample, it showed that the self-made column had excellent performance and provided a new pretreatment method for the treatment of OTA in grains.