Implementation of Fall Detection System Based on Data Fusion Technology

Xianwei Wang,Hongwu Qin 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.4

This paper mainly discusses a fall detecting method for the elderly, implements the wireless positioning and automatic alarm function. The system is designed with low cost Micro-Electro-Mechanical System (MEMS) inertial measurement unit to measures activities data of the elderly people, which has achieved an accurate attitude determination by Kalman filter for the multi-sensor data fusion algorithm, and transfer information to remote medical monitoring system platform by CDMA network, it makes the elderly get treatment in time after the fall. The experiments show that the system can accurately detect the elderly falling, send out alarms and positioning after a fall, its applying will provide a new security guarantee for the elderly health.

Research on the reinforcement experiment of recycled aggregates based on particle shaping and vacuum cement coating

Shuai Wang,Aixun Wang,Xudong Fu,Keyang Wu,Xianwei Zhang,Yongpeng Tang 한양대학교 청정에너지연구소 2024 Journal of Ceramic Processing Research Vol.25 No.3

Reinforcement of recycled aggregates stands as a pivotal strategy to stimulate their resource utilization. This study proposesa strengthening method of recycled aggregate combined with particle molding and vacuum cement coating, and the keycontrol parameters in the reinforcement process, resultant reinforcement outcomes, failure modes, and water absorptionkinetics were discussed. Experimental findings suggest that diminutive surface particle sizes present amplified challenges forshaping. The particle strength within each size categories demonstrates an initial ascent followed by descent with prolongedshaping, underscoring an optimal reinforcement duration. Excessive shaping precipitates a decline in the property of recycledaggregates, manifested through fracture, crush, and local damage. The moisture content of recycled aggregates undergoesfluctuations throughout the shaping process. Notably, the application of vacuum cement coating markedly ameliorateswater absorption post-particle shaping, thereby augmenting failure mode resilience. Building upon these observations, theframework of “moderate shaping,” “moderate damage,” and “damage-repair integration” is introduced for both internaland external reinforcement. This paradigm aims to bolster the particle strength of recycled aggregates, thus facilitating waterconservation during the scale-up preparation phase. This study can guide the establishment of production facilities tailoredfor recycled concrete and furnish insights for the scaled-up preparation of recycled concrete materials.

Scaffold Engineering with Flavone-Modified Biomimetic Architecture for Vascular Tissue Engineering Applications

Xie Chao,Guo Ting,Wang Wei,Li Gang,Cai Zhou,Chen Shen,Wang Xianwei,Liu Ziyu,Wang Zuyong 한국조직공학과 재생의학회 2022 조직공학과 재생의학 Vol.19 No.4

BACKGROUND: Vascular intimal hyperplasia (IH) is one of the key challenges in the clinical application of smalldiameter vascular grafts. Current tissue engineering strategies focus on vascularization and antithrombotics, yet few approaches have been developed to treat IH. Here, we designed a tissue-engineered vascular scaffold with portulaca flavonoid (PTF) composition and biomimetic architecture. METHOD: By electrospinning, PTF is integrated with biodegradable poly(e-caprolactone) (PCL) into a bionic vascular scaffold. The structure and functions of the scaffolds were evaluated based on material characterization and cellular biocompatibility. Human vascular smooth muscle cells (HVSMCs) were cultured on scaffolds for up to 14 days. RESULTS: The incorporation of PTF and preparation parameters during fabrication influences the morphology of the scaffold, including fibre diameter, structure, and orientation. Compared to the PCL scaffold, the scaffolds integrated with bioactive PTF show better hydrophilicity and degradability. HVSMCs seeded on the scaffold alongside the fibres exhibit fusiform-like shapes, indicating that the scaffold can provide contact guidance for cell morphology alterations. This study demonstrates that the PCL/PTF (9.1%) scaffold inhibits the excessive proliferation of HVSMCs without causing cytotoxicity. CONCLUSION: The study provides insights into the problem of restenosis caused by IH. This engineered vascular scaffold with complex function and preparation is expected to be applied as a substitute for small-diameter vascular grafts.

Large-scale Field Tests of the Performance of Geogrid-reinforced Piled Embankment over Soft Soil

Gang Wang,Xianwei Zhang,Xinyu Liu,Zhixiong Chang,Zhihai Liu 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.2

When constructing superstructures on soft soils, geogrid-reinforced embankments and pile-supported embankments are used widely to improve the soft foundation and prevent issues including excessive settlements and large lateral displacements, so it is crucial to understand and evaluate their performance systematically. This study focuses on a case of piled embankments for a motor-racing circuit under construction in China. Two large-scale field tests of pile-supported embankments with and without reinforcement were carried out to investigate the effect of geosynthetic reinforcement on the improvement of embankments. During long-term monitoring, instruments in the test sites measured earth pressures, settlements, lateral displacements, and pore water pressures, and the performances of the reinforced or unreinforced embankments were examined. Test results from the two test sites under similar loading are compared, and it is concluded that the geosynthetic-reinforcement considerably influences the improvement of load transfer and diminishment of total and differential settlements. The lateral restraint provided by the geogrids also reduced the lateral soil displacement and the influence of subsoil depth. The smaller excessive pore water pressures in the site with reinforcement were associated with the enhanced load transfer due to the geogrids. This study provides an important reference for the design and construction of this circuit and other related projects.

Mechanism of lithium storage in MoS2 and the feasibility of using Li2S/Mo nanocomposites as cathode materials for lithium-sulfur batteries.

Fang, Xiangpeng,Guo, Xianwei,Mao, Ya,Hua, Chunxiu,Shen, Lanyao,Hu, Yongsheng,Wang, Zhaoxiang,Wu, Feng,Chen, Liquan Wiley-VCH 2012 Chemistry, an Asian journal Vol.7 No.5

<P>The most-popular strategy to improve the cycling stability and rate performance of the sulfur electrode in lithium-sulfur (Li-S) batteries is to astrict the sulfur in a conducting medium by using complicated chemical/physical processing. Lithium sulfide (Li(2)S) has been proposed as an alternative electrode material to sulfur. However, for its application, it must meet challenges such as high instability in air together with all of the drawbacks of a sulfur-containing electrode. Herein, we report the feasibility of using Li(2)S, which was obtained by electrochemical conversion of commercial molybdenum disulfide (MoS(2)) into Li(2)S and metallic molybdenium (Mo) at low voltages, as a high-performance active material in Li-S batteries. Metallic Mo prevented the dissolution of lithium polysulfides into the electrolyte and enhanced the conductivity of the sulfide electrode. Therefore, the in situ electrochemically prepared Li(2)S/Mo composite exhibited both high cycling stability and high sulfur utilization.</P>

Manuscript numerical simulation on ultra-precision polishing of monocrystalline silicon by SPH method

Xiu Lei,Lv Gang,Xu Yan,Qiao Yang,Jiang Hai,Wang Xianwei,Ye Xia 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.7

Ultra-precision polishing is an important processing method for monocrystalline silicon, in order to improve the machining efficiency and obtain good machining quality, it is necessary to investigate the material removal process and process parameters of ultra-precision polishing. Smoothed particle hydrodynamics (SPH) is a meshless method with good self-adaptability, it can be used in the simulation of ultra-precision polishing which has high speed deformation characteristics. The calculation model and SPH analysis model of ultraprecision polishing are established according to the principle of ultra-precision polishing, SPH method is used to simulate and analyze ultra-precision polishing of the monocrystalline silicon. The material removal process of ultra-precision polishing is investigated, the effects of abrasive size and indentation depth on the equivalent plastic strain (PEEQ), Mises stress and the force of abrasive is investigated. The result is that, at the different time of ultra-precision polishing, the maximum PEEQ is different, but the difference is not obvious; the X direction force of the abrasive increases with the indentation depth; the size of abrasive has a great influence on the soft coefficient of stress state in ultra-precision polishing. According to the simulation results, it is possible to optimize the technological parameters of ultra-precision polishing, and provide the theoretical guidance for practical production.