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Stabilization of a Coupled ODE-wave System with Disturbances
Lu Lu,Yu-Long Zhang,Jun-Min Wang,Dong-Xia Zhao 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.3
This paper is devoted to stabilizing an ODE-PDE coupled system with boundary disturbance, where the PDE is chosen to be a wave equation with viscous damping. Applying the active disturbance rejection control (ADRC) technic, the unknown disturbance is estimated by the extended state observer (ESO). Assuming the absence of disturbance, the dynamic boundary connection is designed. The methods of spectral analysis and separation of operator are applied, which ensures the Riesz basis property as well as the spectrum determined growth condition. The exponential stability of the coupled system without disturbance is then concluded. Finally, combining the disturbance estimation and the dynamic boundary connection, a feedback controller designed to stabilize the coupled system, and the closed-loop system is proved to be asymptotically stable.
Effect of nano-composite materials on repair of ligament injury in sports detoxification
Lu, Chunxia,Lu, Gang,Dong, Weixin,Liu, Xia Techno-Press 2022 Advances in nano research Vol.13 No.3
Extraordinary properties of nanocomposites make them a primary replacement for many conventional materials. Anterior cruciate ligament (ACL) reconstruction, which is a frequent surgery in sport activities, is one of the fields in which nanocomposites could be utilized. In the present study, the mechanical properties of different porous scaffolds made from graphene nano-composites are presented ad load bearing capacity of these materials is calculated using finite element method. The numerical results are further compared with experimental published data. In addition, several geometrical and material parameters are analyzed to find the best configuration of nanocomposite scaffolds in reconstruction of ACL. Moreover, coating of detoxification chemicals are extremely easier on the nano-structured materials than conventional one. Detoxification potential of nano-composites in the injured body are also discussed in detail. The results indicated that nano-composite could be successfully used in place of auto- and allografts and also instead of conventional metallic screws in reconstruction of ACL.
Lu Wu,Li Xia Tan,Fen Fang Gong,Yu Xia,Rui Ge Chu,Hua Sheng Yang 한국식품과학회 2021 Food Science and Biotechnology Vol.30 No.5
This study was designed to evaluate theabsorption promoting capacity of Maillard Reaction Products(MRPs) produced during the stir-frying process ofHordei Fructus Germinatus on catechin, ferulic acid,quercetin and kaempferol by the ex vivo rat everted gut sacmodel, in situ single-pass intestinal perfusion model andthe whole animal model. Moreover, verapamil, EDTA andmannitol were used for determining the transport mechanismof catechin, ferulic acid, quercetin and kaempferol. The tight junction (TJ) proteins including zonula occudens-1(ZO-1) and claudin-1 were chosen to investigate thepromoting mechanism of MRPs by quantitative real-timePCR (qRT-PCR) and western blot analyses. The resultsshowed that the MRPs produced during the stir-fryingprocess of Hordei Fructus Germinatus could improve theintestinal absorption of catechin, ferulic acid, quercetin andkaempferol. And the absorption-promoting effect of MRPswas related to chelating effect and the reduced expressionof claudin-1 and ZO-1. Our results suggested that MRPscould be promising oral absorption promoters, which mightbe another processing mechanism of Hordei FructusGerminatus.
Dynamic analysis of coupled train - ladder track - elevated bridge system
Xia, He,Deng, Yushu,Xia, Chaoyi,De Roeck, G.,Qi, Lin,Sun, Lu Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.47 No.5
As a new type of vibration reduction, the ladder track system has been successfully used in engineering. In this paper, a numerical model of the train-track-viaduct system is established to study the dynamic responses of an elevated bridge with ladder track. The system is composed of a vehicle submodel, a track submodel and a bridge submodel, with the measured track irregularities as the system self-excitation. The whole time histories of a train running through an elevated bridge with $3{\times}27m$ continuous PC box girders are simulated. The dynamic responses of the bridge such as deflections, lateral and vertical accelerations, and the vehicle responses such as derailment factors, offload factors and car-body accelerations are calculated. The calculated results are partly validated through the comparison with the experimental data. Compared to the common slab track, adapting the ladder sleeper can effectively reduce the accelerations of the bridge girder, and also reduce the car-body accelerations and offload factors of the train vehicle.
Xia Chen,Tingjie Lu,Longfei Guo,Yu Shen,Chenguang Wang 보안공학연구지원센터 2014 International Journal of Smart Home Vol.8 No.6
Some studies have shown that the attitude and intention of using mobile LBS is strongly influenced by the privacy factor. Since LBS bears prominent privacy attribute, our study selects the aggregation form based on Microblog content in the LBS of SinaMicroblog, namely, LBS Microblog, asthe object of study, acquires an actual Microblog user data sample of over 30,000 items, with over 8.64 million Microblog postings and 20 million Microblog re-postings of these users, conducts a contrastive research on the adoption behavior in LBS of users at Hub nodes and common nodes in social network through relative analysis, and discusses the diffusion rule of LBS through BASS model. The study finds that the structure attribute of users in social network has strong influence on the adoption rule of LBS; the adoption of different types of LBS by users is obviously in consistency; LBS is remarkably influenced by emergencies related to privacy.
On the role of surface diffusion in determining the shape or morphology of noble-metal nanocrystals
Xia, Xiaohu,Xie, Shuifen,Liu, Maochang,Peng, Hsin-Chieh,Lu, Ning,Wang, Jinguo,Kim, Moon J.,Xia, Younan National Academy of Sciences 2013 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.110 No.17
<P>Controlling the shape or morphology of metal nanocrystals is central to the realization of their many applications in catalysis, plasmonics, and electronics. In one of the approaches, the metal nanocrystals are grown from seeds of certain crystallinity through the addition of atomic species. In this case, manipulating the rates at which the atomic species are added onto different crystallographic planes of a seed has been actively explored to control the growth pattern of a seed and thereby the shape or morphology taken by the final product. Upon deposition, however, the adsorbed atoms (adatoms) may not stay at the same sites where the depositions occur. Instead, they can migrate to other sites on the seed owing to the involvement of surface diffusion, and this could lead to unexpected deviations from a desired growth pathway. Herein, we demonstrated that the growth pathway of a seed is indeed determined by the ratio between the rates for atom deposition and surface diffusion. Our result suggests that surface diffusion needs to be taken into account when controlling the shape or morphology of metal nanocrystals.</P>
Sparse Polynomial Mapping for Manifold Learning
Ying Xia,Qiang Lu,Hae-Young Bae 보안공학연구지원센터(IJSIP) 2014 International Journal of Signal Processing, Image Vol.7 No.6
Manifold learning is an approach for nonlinear dimensionality reduction and has been a hot research topic in the field of computer science. A disadvantage of manifold learning methods is, however, that there are no explicit mappings from the high-dimensional feature space to the low-dimensional representation space. It restricts the application of manifold learning methods in many practical problems such as target detection and classification. Previously, some methods have been proposed to provide linear or nonlinear mappings for manifold learning methods. However, a disadvantage of all these methods is that the learned projective functions are combinations of all the original features, thus it is often difficult to interpret the results. Moreover, the dense projection matrices of these approaches lead to a high cost of computation and storage. In this paper, a sparse polynomial mapping approach is proposed for manifold learning. We first get the low-dimensional representations of the high-dimensional input data by using a manifold learning method, and then a 1-based simplified polynomial regression is used to get a sparse polynomial mapping between the high-dimensional data and their low-dimensional representations. In particular, we apply this to the method of Laplacian eigenmap and derive a sparse nonlinear manifold learning algorithm, which is named sparse locality preserving polynomial embedding. Experimental results on real-world data show the effectiveness of our approach.
Gen-Xia Liu,Shu Ma,Yao Li,Yan Yu,Yi-Xiang Zhou,Ya-Die Lu,Lin Jin,Zi-Lu Wang,Jin-Hua Yu 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-
The putative tumor suppressor microRNA let-7c is extensively associated with the biological properties of cancer cells. However, the potential involvement of let-7c in the differentiation of mesenchymal stem cells has not been fully explored. In this study, we investigated the influence of hsa-let-7c (let-7c) on the proliferation and differentiation of human dental pulp-derived mesenchymal stem cells (DPMSCs) treated with insulin-like growth factor 1 (IGF-1) via flow cytometry, CCK-8 assays, alizarin red staining, real-time RT-PCR, and western blotting. In general, the proliferative capabilities and cell viability of DPMSCs were not significantly affected by the overexpression or deletion of let-7c. However, overexpression of let-7c significantly inhibited the expression of IGF-1 receptor (IGF-1R) and downregulated the osteo/odontogenic differentiation of DPMSCs, as indicated by decreased levels of several osteo/odontogenic markers (osteocalcin, osterix, runt-related transcription factor 2, dentin sialophosphoprotein, dentin sialoprotein, alkaline phosphatase, type 1 collagen, and dentin matrix protein 1) in IGF-1-treated DPMSCs. Inversely, deletion of let- 7c resulted in increased IGF-1R levels and enhanced osteo/odontogenic differentiation. Furthermore, the ERK, JNK, and P38 MAPK pathways were significantly inhibited following the overexpression of let-7c in DPMSCs. Deletion of let-7c promoted the activation of the JNK and P38 MAPK pathways. Our cumulative findings indicate that Let-7c can inhibit the osteo/odontogenic differentiation of IGF-1-treated DPMSCs by targeting IGF-1R via the JNK/P38 MAPK signaling pathways.