Mechanical Properties of Recycled Concrete Reinforced by Basalt Fiber and Nano-silica

Yonggui Wang,Xuetong Zhang,Jinjin Fang,Xingguo Wang 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.8

In this study, basalt fiber (BF) and nanosilica (NS) were used to improve the mechanical properties of recycled concrete (RC), thereby promoting its utilization. The effect of BF and NS on the impact performance of RC was studied using the split Hopkinson pressure bar (SHPB) test. The internal microstructure of RC was analyzed by scanning electron microscopy, mercury intrusion porosimetry and nuclear magnetic resonance test. The results showed that, as the strain rate increased, the destruction mode transitioned from fracturing to crushing. Moreover, the impact compressive strength, dynamic increase factor, and total impact toughness increased. The replacement rate has little to no influence on the failure state, impact compressive strength and specific energy absorption. BF is conducive to enhancing the integrity and improving the impact compressive strength, peak strain and impact toughness. NS can reduce the pore content of mortar and the corrosion effect of the fiber surface, enhancing the compactness of the mortar and the bridging effect of the fiber. With an increase in NS content, the impact compressive strength, peak strain, and impact toughness increase, leading to greater destruction integrity. The results show that BF and NS can more effectively enhance the mechanical properties of RC.

Fabrication of Protective Textile with N-doped TiO2 Embedded Citral Microcapsule Coating and Its Air Purification Properties

Shuo Wang,Huihui Ding,Yishi Zhao,Yonggui Li,Wei Wang 한국섬유공학회 2020 Fibers and polymers Vol.21 No.2

The protective textile was successfully prepared using N-doped TiO2 (N-TiO2) embedded citral microcapsule coating. N-TiO2 loaded citral microcapsules were synthesized through interfacial polymerization. Results showed the average diameter of N-TiO2 loaded citral microcapsule with core/shell (Mcitral : MHDI) 2:1 was 1.069 μm. Its encapsulation efficiency was 75.63 %. The citral content from finished cotton fabric measured by gas chromatography was up to 2.90 mg/g (weight of essence: weight of fabric). The essence release content of citral was nearly 50 % of their aroma after 12 weeks, exhibiting good physical function for air purification. Additionally, aromatic textile coated with N-TiO2 embedded citral microcapsules also exhibited photocatalytic activity for the degradation of formaldehyde under visible light irradiation. This functionalfabric would have potential applications in the air purification filed due to the chemical and physical dual effect.

Model Parameter Correction Algorithm for Predictive Current Control of SMPMSM

Yonggui Li,Shuang Wang,Hua Ji,Jian Shi,Surong Huang 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.3

The inaccurate model parameters in the predictive current control of surface-mounted permanent magnet synchronous motor (SMPMSM) affect the current dynamic response and steady-state error. This paper presents a model parameter correction algorithm based on the relationship between the errors of model parameters and the static errors of dq-axis current. In this correction algorithm, the errors of inductance and flux are corrected in two steps. Resistance is ignored. First, the proportional relations between inductance and d-axis static current errors are utilized to correct the error of model inductance. Second, the flux is corrected by utilizing the proportional relations between flux and q-axis static current errors under the condition that inductance is corrected. An experimental study with a 100 W SMPMSM is performed to validate the proposed algorithm.

Mechanical Properties Improvement of Nanoclay Addition Epoxy 3D Orthogonal Woven Composite Material

Cong Wang,Xiaoping Gao,Yonggui Li 한국섬유공학회 2019 Fibers and polymers Vol.20 No.7

In this study, the influence of nanoclay on mechanical properties of epoxy/3D orthogonal glass fiber wovencomposite was studied. The DK2 polymer-grade organic nanoclay modification composite specimen reinforced with 3Dorthogonal woven fabric/epoxy was manufactured by means of Resin Infusion under Flexible Tooling (RIFT) process. Firstly, the modification mechanism with nanoclay was characterized by means of Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction (XRD) and transmission electron microscope (TEM). Secondly, as far as the tensile behaviorbetween the fiber/matrix of the composite was concerned, the modification process was optimized by means of nonlinearleast square fitting. The results show that the bonding strength between the fiber and matrix was improved and thedelamination and debonding between fiber and matrix was retarded and shifted to cohesive failure of the matrix due to thenanoclay modification with respect to results from FT-IR, XRD and TEM. The tensile strength and modulus of compositewere increased by 23.32 % and 16.42 % respectively due to 3 of nanoclay addition. The contact angle also shows that thedispersion effect and wettability at this state. The tensile stress-strain curve was fitted by applying nonlinear fitting. It can beconcluded that there has a good modification effect with 3 wt% of nanoclay addition.

Model Parameter Correction Algorithm for Predictive Current Control of SMPMSM

Li, Yonggui,Wang, Shuang,Ji, Hua,Shi, Jian,Huang, Surong The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.3

The inaccurate model parameters in the predictive current control of surface-mounted permanent magnet synchronous motor (SMPMSM) affect the current dynamic response and steady-state error. This paper presents a model parameter correction algorithm based on the relationship between the errors of model parameters and the static errors of dq-axis current. In this correction algorithm, the errors of inductance and flux are corrected in two steps. Resistance is ignored. First, the proportional relations between inductance and d-axis static current errors are utilized to correct the error of model inductance. Second, the flux is corrected by utilizing the proportional relations between flux and q-axis static current errors under the condition that inductance is corrected. An experimental study with a 100 W SMPMSM is performed to validate the proposed algorithm.

Positive Observer Design for Positive Markovian Jump Systems with Mode–dependent Time–varying Delays and Incomplete Transition Rates

Jiyang Wang,Wenhai Qi,Xianwen Gao,Yonggui Kao 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.2

The paper is concerned with positive observer design for positive Markovian jump systems with incompletetransition rates and time delays that are mode-dependent and time-varying. Firstly, by applying an appropriateco-positive type Lyapunov-Krasovskii function and free-connection weighting vectors, sufficient conditions areproposed to ensure stochastic stability of the error positive system and existence of the positive observer. All theproposed conditions are derived in linear programming. Finally, an example is given to demonstrate the validity ofthe main results.

Robust Finite-time Control for Neutral Systems with Time-varying Delays via Sliding Mode Observer

Shuqin Wang,Baoping Jiang,Cunchen Gao,Yonggui Kao 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.5

This paper is concerned with the problem of robust finite-time sliding mode control (SMC) for a classof continuous-time uncertain neutral systems with time-varying delays. Firstly, based on the constructed slidingmode observer, an integral sliding surface is put forward on the estimation space. Secondly, the synthesized SMClaw guarantees the finite-time reachability of the predefined sliding surface. Thirdly, through finite-time stabilityanalysis, sufficient conditions are established to guarantee the required performance of the system during bothreaching phase and sliding motion phase. Finally, a practical example is provided to verify the effectiveness of theproposed method.

Improvement on Fatigue Performance of 3-D Orthogonal Woven Composite with Nanoclay Modification

Xiaoping Gao,Cong Wang,Wei Wu,Yonggui Li 한국섬유공학회 2021 Fibers and polymers Vol.22 No.1

3-D orthogonal woven composite (3DOWC) has attracted great interest in the industrial and energy fields, due totheir excellent mechanical properties. However, due to the poor bonding strength between fiber and epoxy, it’s mechanicalproperties, especially the fatigue behavior are critical for structural design in the practical applications. The nanoclaymodification composite reinforced with 3-D orthogonal woven fabric (3DOWF)/epoxy resin was fabricated using resininfusion under flexible tooling (RIFT). The quasi-static tensile and fatigue behavior of 3-D orthogonal woven composite(3DOWC) in 0 ° and 90 ° inclined to warp direction were evaluated and compared to the pristine one or composite materialnot modified with nanoclay. The fatigue behavior such as the S-N curves, stress-strain curves, stiffness degradation curvesand residual strength were also obtained. The results show that the tensile strength, modulus and the fatigue life wereimproved effectively due to nanoclay modification. However, the stiffness degradation of nanoclay addition in 90 ° directionwas decreased.

Development of Cemented Carbide Industry of China

Shao Peng,Fangling Zou,Yonggui Zhou,Huan Wang 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1

Through the review of developing course of China cemented carbide industry, the writer of this paper at the first time generalizes it into five stages. The writer analyses China cemented carbide industry present status in aspects of produce technology, product structure, operation and management etc. Mean while by analysis of existed shortages in cemented carbide industry, the write considers that it also has three advantages in resource and scale, industry foundation and categories, market and price, and brought out some suggestion and imagination for the future develpment of China cemented carbide industry.

Validation of the Thyrotoxicosis-associated Insomnia Model Induced by Thyroxine through Sympathetic Stimulation: Face, Construct and Predictive Perspectives

Zhifu Ai,Hongwei He,Tingting Wang,Liling Chen,Chunhua Huang,Changlian Chen,Pengfei Xu,Genhua Zhu,Ming Yang,Yonggui Song,Dan Su 한국뇌신경과학회 2021 Experimental Neurobiology Vol.30 No.6

Insomnia has become a common central nervous system disease. At present, the pathogenesis of insomnia is not clear. Animal models can help us understand the pathogenesis of the disease and can be used in transformational medicine. Therefore, it is very necessary to establish an appropriate model of insomnia. Clinical data show that insomnia patients with high levels of thyroxine and often accompanied by cardiovascular problems, a common mechanism underlying all of these physiological disruptions is the sympathetic nervous system. Combined with the characteristics of chronic onset of clinical insomnia, an insomnia model induced by long-term intraperitoneal injection of thyroid hormone has been created in our laboratory. In this paper, the insomnia-like state of the model was evaluated based on three validity criteria. Face validity has been demonstrated in metabolism, the Morris water maze, electrocardiogram (ECG) and electroencephalogram (EEG). Structure validity has been proved by the results of targeted metabolomics. After treatment with diazepam, a commonly used clinical anti-insomnia drug, the above physiological and pathological disorders were reversed. The results of comprehensive analysis show that the established thyrotoxicosis-associated insomnia model meets the validity requirement to establish an appropriate animal model of insomnia. The model presented in this article might help to study pathogenetic mechanisms of clinical insomnia, as well as to test promising methods of insomnia treatment.