Facile Fabrication of Electrospun Silica Nanofibrous Membrane with Hydrophobic, Oleophilic and Breathable Performances

Meng-Jie Chang,Xiao-Jiao Chai,Wen-Na Cui,Jun Liu 한국섬유공학회 2018 Fibers and polymers Vol.19 No.4

We report a simple and versatile method to prepare hydrophobic composite SiO2 membrane. The electrospun SiO2 membrane was selected due to its good flexibility and thermal stability. The hydrophobic SiO2 membrane was succussfully prepared by simply evaporating a thin polydimethylsiloxane (PDMS) layer on the fiber surface. The characterization results show that the PDMS layer is too thin to be observed. The PDMS coating has no influence on the porous structure of the fibrous membrane, but imparts the good hydrophobicity and oleophilicity to the SiO2 nanofibers. As demonstration, the hydrophobic SiO2-PDMS membrane displays good oil absorption performance from the oil/water mixture, as well as filtration membrane for oil/water separation. Additionally, due to the proper pore size and hydrophobic surface, the SiO2- PDMS membrane shows good waterproof performance and breathability at the same time.

Effect of raw materials on the properties of ZrB2-YAG-Al2O3 multi-phase ceramics

Jie-Guang Song,Fang Wang,Da-Ming Du,Yin-Yan Ju,Shi-Bin Li,Gang-Chang Ji,Lian-Meng Zhang 한양대학교 세라믹연구소 2014 Journal of Ceramic Processing Research Vol.15 No.2

ZrB2 belongs to a class of ceramics defined ultra-high-temperature ceramics with extremely high melting temperatures, but ZrB2 ceramics is difficultly sintered and easily oxidized. To make ZrB2 ceramics possess the high relative density and the better oxidation resistance. The effects of raw materials on the properties of ZrB2 composite were investigated. YAG and Al2O3 help for the densification of ZrB2 ceramics. Fracture toughness of sintered ceramics with coated powder is higher than that of sintered ceramics with mixed powder. The mechanical property of ZrB2-YAG-Al2O3 materials is higher than that of ZrB2-YAG materials. Oxidation layer thickness of sintered ceramics with coated powder is thinner than that of sintered ceramics with mixed powder. These results show the sintered ZrB2 based multi-phase ceramics with coated microstructure help to increase the mechanical properties and oxidation resistance. The oxidation resistance of ZrB2-YAG-Al2O3 ceramics is better than that of ZrB2-YAG materials.

Preparation and properties of ZrB2-YAG-Al2O3 ceramics

Jie-Guang Song,Gang-Chang Ji,Shi-Bin Li,Yang-Liang Li,Da-Ming Du,Lian-Meng Zhang,Yin-Yan Ju 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.4

ZrB2, YAG and Al2O3 are widely applied because of some excellent properties, but ZrB2 is easily oxidized in high-temperature air. To achieve better properties in ZrB2 ceramics, high-density ZrB2-YAG-Al2O3 ceramics were prepared. Below 1000℃, the shrinkage of ZrB2-YAG-Al2O3 ceramics is less than that of ZrB2-YAG ceramics. From 1000℃ to 1600℃, the second largest shrinkage occurs. Above 1600℃, the shrinkage of ZrB2-YAG-Al2O3 ceramics is more than that of ZrB2-YAG ceramics. The fracture toughness of sintered ceramics from coated raw materials is higher than that of sintered ceramics with mixed raw materials with the same phases and phase content, the fracture toughness of ZrB2-YAG-Al2O3 ceramics is higher than that of ZrB2-YAG ceramics with the same raw materials. The weight gain of all types of ceramics is increased with all increase in the oxidation temperature, the weight gain of ceramics is reduced with all increase in the YAG-Al2O3 content and Al2O3 proportion, especially above 1500℃. ZrB2, YAG and Al2O3 are widely applied because of some excellent properties, but ZrB2 is easily oxidized in high-temperature air. To achieve better properties in ZrB2 ceramics, high-density ZrB2-YAG-Al2O3 ceramics were prepared. Below 1000℃, the shrinkage of ZrB2-YAG-Al2O3 ceramics is less than that of ZrB2-YAG ceramics. From 1000℃ to 1600℃, the second largest shrinkage occurs. Above 1600℃, the shrinkage of ZrB2-YAG-Al2O3 ceramics is more than that of ZrB2-YAG ceramics. The fracture toughness of sintered ceramics from coated raw materials is higher than that of sintered ceramics with mixed raw materials with the same phases and phase content, the fracture toughness of ZrB2-YAG-Al2O3 ceramics is higher than that of ZrB2-YAG ceramics with the same raw materials. The weight gain of all types of ceramics is increased with all increase in the oxidation temperature, the weight gain of ceramics is reduced with all increase in the YAG-Al2O3 content and Al2O3 proportion, especially above 1500℃.

SEASONAL VARIABILITY OF CARBONATE SYSTEM CHARACTERISTICS IN A CORAL REEF ECOSYSTEM, SOUTHERN TAIWAN

Pei-Jie Meng,Ming-Yih Leu,Cheng-Hao Tang,Chung-Chi Chen,Kwee-Siong Tew,Chia-Ming Chang 한국수산과학회 양식분과 2015 한국수산과학회 양식분과 학술대회 Vol.2015 No.5

Solvothermal Synthesis of Reduced Graphene Oxide/Ferroferric Oxide Hybrid Composites with Enhanced Microwave Absorption Properties

Ruiwen Shu,Meng Wang,Yingying Yang,Siyu Chang,Gengyuan Zhang,Ying Gan,Jianjun Shi,Jie He 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.12

In this work, reduced graphene oxide (RGO)/ferroferric oxide (RGO/Fe3O4) hybrid composite was successfully fabricated by a facile one-step solvothermal method. The structure, chemical composition, morphology and magnetic properties of the samples were investigated in detail. Fe3O4 microspheres with an average diameter of 250 nm were uniformly anchored on the surface of the RGO sheets without large aggregation. Moreover, the results demonstrated that the hybrid composite exhibited obviously enhanced microwave absorption properties compared with the pure Fe3O4 microspheres. The minimum reflection loss (RL) of the hybrid composite reached -36.8 dB at 17.2 GHz with a thickness of 5.0mm and its effective absorption bandwidth (lower than - 10 dB) was 3.9 GHz with a thickness of 2.5 mm. Significantly, the hybrid composite exhibited a dual-waveband absorption characteristic covering the C and Ku bands. Besides, the relationship between the matching thickness and peak frequency was reasonably explained according to the quarter-wavelength matching theory. Therefore, the obtained composite was a promising candidate for application in microwave absorption.

Highly Uniform Core/Shell Structured CoFe2O4/MIL-100(Fe) Nanofibers for Efficient Visible Light Photocatalysis

Jun Liu,Meng Sun,Meng-Jie Chang,Si-Meng Fan,Qian Hui,Fu-Rong Ni,Bin Yuan 한국섬유공학회 2021 Fibers and polymers Vol.22 No.2

Novel CoFe2O4/MIL-100(Fe) (CFO/MIL-100(Fe)) core/shell nanofibers were prepared by successive ionic layeradsorption and reaction (SILAR) assembly of MIL-100(Fe) on electrospun CoFe2O4 nanofibers. The MIL-100(Fe) shellswere constructed on the dispersed CoFe2O4 fiber surface with high uniformity, homogeneous thickness and high stability. Due to the inherent porosity of MIL-100(Fe), a higher specific surface area of 225.77 m2/g is achieved for the CFO/MIL-100(Fe)-10 sample. The formed CFO/MIL-100(Fe) catalysts exhibit high catalytic activity towards degradation of rhodamineB (RhB) under visible light irradiation. The photocatalytic activity remains above 77 % within 60 min illumination after fourcycles. Due to the simple synthetic method, highly uniform structure, strong magnetic recoverable, as well as goodphotocatalytic performance, the obtained CFO/MIL-100(Fe) core/shell nanofibers could be promising photocatalysts forpractical application.

Molecular cloning, characterization, and functional analysis of a gene encoding 3-hydroxy-3-methylglutaryl-coenzyme A synthase from Matricaria chamomilla

Feng Xu,Tingting Tao,Qiangwen Chen,Xiangxiang Meng,Jiaping Yan,Jie Chang 한국유전학회 2016 Genes & Genomics Vol.38 No.12

3-Hydroxy-3-methylglutaryl-CoA synthase (HMGS) catalyzes the condensation of acetyl-CoA and acetoacetyl- CoA to form 3-hydroxy-3-methylglutaryl-CoA as the first committed enzyme in the mevalonate (MVA) pathway. HMGS plays an important role in the biosynthesis of the sesquiterpene, which is the main constituent of essential oil in Matricaria chamomilla. In this paper, a HMGS gene designated as McHMGS (GenBank Accession No. KU529970) was successfully cloned from M. chamomilla. The full-length cDNA of McHMGS was 1495-bp and contained a 1374-bp open reading frame. It encoded a 458-amino-acid protein with a calculated molecular weight of about 50.7 kDa and isoelectric point of 5.69. Sequence comparison revealed that McHMGS showed extensive homology with HMGSs from other plant species. Phylogenetic tree analysis indicated that McHMGS is clustered with the HMGS of Asteraceae in the dicotyledoneae clade. Further functional complementation of McHMGS in hmgsdeficient mutant yeast strain YSC6274 demonstrated that cloned McHMGS cDNA encodes a functional HMGS and mediates the MVA biosynthesis in yeasts. The tissue expression pattern analysis revealed that McHMGS expression level is highest in the flowers and lowest in the stems. Quantitative real-time PCR analysis showed that the expression of McHMGS was induced by MeJA, and the expression level is highest 24 h after induction. The characterization and expression of McHMGS can help in further studying the role of McHMGS gene in the biosynthesis of sesquiterpene in M. chamomilla.