Preparation and Performance of Aluminosilicate Fibrous Porous Ceramics Via Vacuum Suction Filtration

Qingqing Wang,Shaofeng Zhu,Zhenfan Chen,Tong Zhang 한국재료학회 2024 한국재료학회지 Vol.34 No.1

This study successfully prepared high-porosity aluminosilicate fibrous porous ceramics through vacuum suction filtration using aluminosilicate fiber as the primary raw material and glass powder as binder, with the appropriate incorporation of glass fiber. The effects of the composition of raw materials and sintering process on the structure and properties of the material were studied. The results show that when the content of glass powder reached 20 wt% and the samples were sintered at the temperature of 1,000 °C, strong bonds were formed between the binder phase and fibers, resulting in a compressive strength of 0.63 MPa. When the sintering temperatures were increased from 1,000 °C to 1,200, the open porosity of the samples decreased from 89.08 % to 82.38 %, while the linear shrinkage increased from 1.13 % to 10.17 %. Meanwhile, during the sintering process, a large amount of cristobalite and mullite were precipitated from the aluminosilicate fibers, which reduced the performance of the aluminosilicate fibers and hindered the comprehensive improvement in sample performance. Based on these conditions, after adding 30 wt% glass fiber and being sintered at 1,000 °C, the sample exhibited higher compressive strength (1.34 MPa), higher open porosity (89.13 %), and lower linear shrinkage (5.26 %). The aluminosilicate fibrous porous ceramic samples exhibited excellent permeability performance due to their high porosity and interconnected three-dimensional pore structures. When the samples were filtered at a flow rate of 150 mL/min, the measured pressure drop and permeability were 0.56 KPa and 0.77 × 10-6 m2 respectively.

Graphene Oxide/Polyester Fabric Composite by Electrostatic Self-Assembly as a New Recyclable Adsorbent for the Removal of Methylene Blue

Di Wang,Dawei Li,Pengfei Lv,Qingqing Wang,Yang Xu,Qufu Wei 한국섬유공학회 2018 Fibers and polymers Vol.19 No.8

A novel graphene oxide/polyester (GO/PET) composite fabric as a recyclable adsorbent was prepared via electrostatic self-assembly. The structure, morphology, and properties of the GO/PET composite fabrics were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier transformed infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and contact angle (CA), respectively. The absorption property was evaluated by the absorption amount and removal efficiency of methylene blue (MB) solution on the GO/PET composite fabric. The results indicated that the absorption amount was found to be 21.80 mg/g and the removal efficiency reached 99.93 % under the experimental conditions of GO concentration of 2 mg/ml, initial concentration of 50 mg/l, and area of 64 cm2. The experimental parameters were investigated including the concentration of GO, the initial concentration of MB solutions, and adsorbent area. Simultaneously, according to a series of dynamic analysis, the absorption process revealed that the kinetics was well-described by pseudo-second-order model. This study showed that the GO/PET composite fabric could be a recyclable, efficient adsorbent material for the environmental cleanup.

Polyetheretherketone implants with hierarchical porous structure for boosted osseointegration

Zhiyong Chen,Yu Chen,Yang Wang,JiaJia Deng,Xin Wang,Qingqing Wang,Yuehua Liu,Jiandong Ding,Lin Yu 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Good osseointegration is the key to the long-term stability of bone implants. Thermoplastic polyetheretherketone (PEEK) has been widely used in orthopedics; however, its inherent biological inertia causes fibrous tissue to wrap its surface, which leads to poor osseointegration and thus greatly limits its clinical applications. Methods Herein, we developed a facile yet effective surface modification strategy. A commonly used sulfonation coupled with “cold pressing” treatment in the presence of porogenic agent formed a three-dimensional hierarchical porous structure on PEEK surface. Subsequently, the effects of porous surface on the in vitro adhesion, proliferation and differentiation of rat bone marrow-derived mesenchymal stem cells (BMSCs) were evaluated. Finally, the osteoinduction and osseointegration of surface-porous PEEK implant were examined in the rat distal femoral defect model. Results In vitro results showed that the surface modification did not significantly affect the mechanical performance and cytocompatibility of PEEK substance, and the porous structure on the modified PEEK substrate provided space for cellular ingrowth and enhanced osteogenic differentiation and mineralization of BMSCs. In vivo tests demonstrated that the surface-porous PEEK implant could effectively promote new bone formation and had higher bone-implant contact rate, thereby achieving good bone integration with the surrounding host bone. In addition, this modification technique was also successfully demonstrated on a medical PEEK interbody fusion cage. Conclusion The present study indicates that topological morphology plays a pivotal role in determining implant osseointegration and this facile and effective modification strategy developed by us is expected to achieve practical applications quickly.

Melatonin protects endothelial progenitor L255cells against AGE-induced apoptosis via autophagy flux stimulation and promotes wound healing in diabetic mice

Haiming Jin,Zengjie Zhang,Chengui Wang,Qian Tang,Jianle Wang,Xueqin Bai,Qingqing Wang,Majid Nisar,Naifeng Tian,Quan Wang,Cong Mao,Xiaolei Zhang,Xiangyang Wang 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

Wound healing is delayed in diabetic patients. Increased apoptosis and endothelial progenitor cell (EPC) dysfunction are implicated in delayed diabetic wound healing. Melatonin, a major secretory product of the pineal gland, promotes diabetic wound healing; however, its mechanism of action remains unclear. Here, EPCs were isolated from the bone marrow of mice. Treatment of EPCs with melatonin alleviated advanced glycation end product (AGE)-induced apoptosis and cellular dysfunction. We further examined autophagy flux after melatonin treatment and found increased light chain 3 (LC3) and p62 protein levels in AGE-treated EPCs. However, lysosome-associated membrane protein 2 expression was decreased, indicating that autophagy flux was impaired in EPCs treated with AGEs. We then evaluated autophagy flux after melatonin treatment and found that melatonin increased the LC3 levels, but attenuated the accumulation of p62, suggesting a stimulatory effect of melatonin on autophagy flux. Blockage of autophagy flux by chloroquine partially abolished the protective effects of melatonin, indicating that autophagy flux is involved in the protective effects of melatonin. Furthermore, we found that the AMPK/mTOR signaling pathway is involved in autophagy flux stimulation by melatonin. An in vivo study also illustrated that melatonin treatment ameliorated impaired wound healing in a streptozotocin-induced diabetic wound healing model. Thus, our study shows that melatonin protects EPCs against apoptosis and dysfunction via autophagy flux stimulation and ameliorates impaired wound healing in vivo, providing insight into its mechanism of action in diabetic wound healing.

Loss of KDM5B ameliorates pathological cardiac fibrosis and dysfunction by epigenetically enhancing ATF3 expression

Wang Bo,Tan Yong,Zhang Yunkai,Zhang Sheng,Duan Xuewen,Jiang Yuyu,Li Tong,Zhou Qingqing,Liu Xingguang,Zhan Zhenzhen 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Excessive cardiac fibrosis is central to adverse cardiac remodeling and dysfunction leading to heart failure in many cardiac diseases. Histone methylation plays a crucial role in various pathophysiological events. However, the role of histone methylation modification enzymes in pathological cardiac fibrosis needs to be fully elucidated. Here, we identified lysine demethylase 5B (KDM5B), a histone H3K4me2/me3 demethylase, as a key epigenetic mediator of pathological cardiac fibrosis. KDM5B expression was upregulated in cardiac fibroblasts and myocardial tissues in response to pathological stress. KDM5B deficiency markedly ameliorated cardiac fibrosis, improved cardiac function, and prevented adverse cardiac remodeling following myocardial infarction (MI) or pressure overload. KDM5B knockout or inhibitor treatment constrained the transition of cardiac fibroblasts to profibrogenic myofibroblasts and suppressed fibrotic responses. KDM5B deficiency also facilitated the transformation of cardiac fibroblasts to endothelial-like cells and promoted angiogenesis in response to myocardial injury. Mechanistically, KDM5B bound to the promoter of activating transcription factor 3 (Atf3), an antifibrotic regulator of cardiac fibrosis, and inhibited ATF3 expression by demethylating the activated H3K4me2/3 modification, leading to the enhanced activation of TGF-β signaling and excessive expression of profibrotic genes. Our study indicates that KDM5B drives pathological cardiac fibrosis and represents a candidate target for intervention in cardiac dysfunction and heart failure.

Experimental Study of the Shear Capacity of Steel Beam-to-L-CFST Column Connections

Qingqing Xiong,Wang Zhang,Zhi-Hua Chen,Yansheng Du,Ting Zhou 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.3

This paper aims to investigate the shear performance of a new and innovative type of vertical stiff ener connection between steel beams and L-shaped columns composed of concrete-fi lled steel tubes connected by transverse and vertical steel plates (L-CFST columns) in high-rise residential buildings. Quasi-static cyclic loading tests were performed on fi ve full-scale specimens to investigate the panel zone behaviours. Based on the experimental results, the hysteretic responses, skeleton curves of the shear force–deformation, ductility, stiff ness degradation, energy dissipation and strain are discussed. The variables studied in these experiments include the joint type, axial compression ratio, cross-sectional area and width-to-thickness ratio of the vertical stiff ener, and presence of concrete. The results indicate that the cross-sectional area of the vertical stiff eners plays a critical role in the performance of the panel zone. Two types of failure modes were observed outside the panel zone: fracturing of the vertical stiff eners and fracturing of the beam fl ange connecting plate. Shear deformation of the panel zone was obvious in the exterior joint specimens, and the corresponding maximum shear deformation reached 0.05 rad. Furthermore, the scopes of the panel zone in the corner and exterior joint specimens were determined by the strain distribution.

Study on the progressive collapse resistance of CP-FBSP connections in LCFST frame structe

Qingqing Xiong,Wenbo Wu,Wang Zhang,Zhihua Chen,Hongbo Liu,Tiancheng Su 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.44 No.3

When the vertical load-bearing members in high-rise structures fail locally, the beam-column joints play an important role in the redistribution of the internal forces. In this paper, a static laboratory test of three full-scale flush flange beam-reinforced connections with side and cover plates (CP-FBSP connection) with double half-span steel beams and single Lshaped columns composed of concrete-filled steel tubes (L-CFST columns) was conducted. The influence of the side plate width and cover plate thickness on the progressive collapse resistance of the substructure was thoroughly analyzed. The failure mode, vertical force-displacement curves, strain variation, reaction force of the pin support and development of internal force in the section with the assumed plastic hinge were discussed. Then, through the verified finite element model, the corresponding analyses of the thickness and length of the side plates, the connecting length between the steel beam flange and cover plate, and the vertical-force eccentricity were carried out. The results show that the failure of all the specimens occurred through the cracking of the beam flange or the cover plate, and the beam chord rotations measured by the test were all greater than 0.085 rad. Increasing the length, thickness and width of the side plates slightly reduced the progressive collapse resistance of the substructures. The vertical-force eccentricity along the beam length reduced the progressive collapse resistance of the substructure. An increase in the connecting length between the beam flange and cover plate can significantly improve the progressive collapse resistance of substructures.

FORMATION AND QUASI-PERIODIC BEHAVIOR OF OUTER SPIRAL RAINBANDS IN A NUMERICALLY SIMULATED TROPICAL CYCLONE

Qingqing LI,Yuqing WANG 한국기상학회 2011 한국기상학회 학술대회 논문집 Vol.2011 No.10-2

Experimental seismic behaviour of L-CFST column to H-beam connections

Wang Zhang,Zhi-Hua Chen,Qingqing Xiong,Ting Zhou,Xian Rong,Yansheng Du 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.26 No.6

In this study, the seismic performance of the connections between L-shaped columns composed of concrete-filled steel tubes (L-CFST columns) and H-beams used in high-rise steel frame structures was investigated. Seven full-scale specimens were tested under quasi-static cyclic loading. The variables studied in the tests included the joint type, the axial compression ratio, the presence of concrete, the width-to-thickness ratio and the internal extension length of the side plates. The hysteretic response, strength degradation, stiffness degradation, ductility, plastic rotation capacity, energy dissipation capacity and the strain distribution were evaluated at different load cycles. The test results indicated that both the corner and exterior joint specimens failed due to local buckling and crack within the beam flange adjacent to the end of the side plates. However, the failure modes of the interior joint specimens primarily included local buckling and crack at the end plates and curved corners of the beam flange. A design method was proposed for the flexural capacity of the end plate connection in the interior joint. Good agreement was observed between the theoretical and test results of both the yield and ultimate flexural capacity of the end plate connection.

Application Study of Fuzzy Reasoning Method for Domain Ontology

Hong Wang,Jian Li,Qingqing Zhang,Weiwei Cai 보안공학연구지원센터 2016 International Journal of Database Theory and Appli Vol.9 No.8

For the representation and reasoning of fuzzy knowledge for domain ontology, the paper presents the reasoning method based on fuzzy ontology. On a basis of the study of civil aviation emergency domain ontology, it gives fuzzy extension model of domain ontology based on fuzzy description logic from the perspectives of fuzzy modifiers and fuzzy concrete domains, and designs fuzzy rules by introducing weight concept and gives the representation and construction process of fuzzy rules on a basis of f-SWRL in connection with the inference application of situation analysis for civil aviation events. The experimental results show that the fuzzy extension method of domain ontology can make up for the issue that the existing domain ontology is inadequate in terms of fuzzy knowledge representation, and provide a good methodological support for making domain ontology perfect and inference application with the reasoning implementation based on fuzzy rules.