325 research outputs found
Synthesis of a composite Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>/poly(SMA-co-BA-co-BZMA-co-DMC) and evaluation of its oil-water separation performance
No full textTo obtain a demulsification material with convenient recovery, high oil-water separation capacity, and excellent reusability, Fe3O4@SiO2 core-shell particles and hydrophilic DMC were introduced into the acrylic ester-based polymer system to prepare a magnetic amphiphilic composite demulsifier, Fe3O4@SiO2/poly(SMA-co-BA-co- BZMA-co-DMC) (Fe3O4@SiO2/PAMCs-P). The molecular structure of Fe3O4@SiO2/PAMCs-P was characterized using FT-IR and XPS, while the morphology was observed using SEM. Additionally, the effects of TEOS, Fe3O4@SiO2 core-shell particles, and DMC dosage on the demulsification performance of the composites were discussed in detail. Fe3O4@SiO2/PAMCs-P exhibited excellent demulsification, oil-water separation, and reusability properties for CTAB-toluene emulsions. Under magnetic field conditions, Fe3O4@SiO2/PAMCs-P achieved saturated separation within 2 h with a separation efficiency of 97.9%. After five consecutive separations, the separation efficiency decreased to 39.1%, but it could be restored to 91.5% of the initial separation efficiency after desorption. These results indicate that Fe3O4@SiO2/PAMCs-P has valuable application potential in emulsified wastewater treatment
mixture treatment
No full textTo acquire a material with simultaneous oil–water emulsion demulsification and oil-absorbing performance, SiO
2 nanoparticles were introduced into the acrylate polymerization system to prepare oil absorbent SiO
2/P (SMA-co-MMA-co-BA) (PSA-SiO
2). PSA-SiO
2 was synthesized from monomers and functional materials, including methyl methacrylate (MMA), butyl acrylate (BA), octadecyl methacrylate (SMA) and SiO
2 hydrophobically modified by vinyltrimethoxysilane. The molecular structure of PSA-SiO
2 was characterized by FT-IR, and its morphology was observed using scanning electron microscopy. In addition, the optimal synthesis conditions for the polymerization system, such as the monomer ratio, the amount of crosslinker and stabilizer and then the particle size and dose of SiO
2, were discussed in detail. PSA-SiO
2 had a decent oil absorbency for pure halogenated and aromatic hydrocarbons (49.10, 56.41, 47.32, 43.45, 36.22, and 30.14 g/g for CH
2Cl
2, CHCl
3, CCl
4, C
2Cl
4, toluene and styrene, respectively). Furthermore, SiO
2, as a functional material, makes composites that possess excellent demulsification properties for oil-in-water emulsions. The oil removal efficiency of CHCl
3 in Tween 80-stabilized and CTAB-stabilized emulsions were 94.88% and 98.11%, respectively. All results indicated that PSA-SiO
2 had valuable potential for oil removal and emulsion treatment. Highlights: An organic–inorganic composite was synthesized by suspension polymerization. The composite was applied for absorbing pure oil or removing oil form water. By modification, the composite acquired the demulsification ability. The composite accomplished one-step demulsification and emulsion treatment. The oil absorption and emulsion treatment could achieve at room temperature.</p
The Study of Xu Wei's Art Idea and Creation Practice Wu Keyu humanity institute of Xiamen University
No full text徐渭在书、诗、画、戏曲诸领域都取得了巨大的艺术成就，因而臣服了无数后人，甚者愿为门下走狗。但何以徐渭会取得如此巨大的成就？几乎所有臣服者都只能用一个字来回答：奇。人奇然后书奇、诗奇、画奇、戏曲亦奇。“奇”果真是徐渭在各领域取得巨大成就的真正原因吗？它的内涵又是什么？要揭开这个答案，必须找到徐渭创作各类艺术的共通的真正指导思想。本文分成三个部分来分别论述徐渭艺术观念的形成、内涵以及在艺术作品中的表现，试图挖掘出贯穿徐渭艺术创作内在的精神。艺术观念是解开徐渭艺术创作实践及艺术风格的钥匙。研究徐渭艺术观念的形成及内涵，知人论世走向艺术家心灵，艺术语境是我们首先必须要面对的问题。在第一章艺术观念形成的...Xu Wei made great success in handwriting, poem, drawing and opera, so countless descendants submitted themselves to him , and even be willing to be the lackeys of him. However, why could Xu Wei make so enormous achievement? Nearly all people who submitted to him can answer with only a word: Strange. The person is strange ,so his handwriting ,poem, drawing and opera are also strange. Is " strangene...学位：文学硕士院系专业：人文学院中文系_文艺学学号：X20040100
The Study of Solutions of Several Systems of Nonlinear Partial Differential Difference Equations
No full textOur main aim is to describe the entire solutions of several systems of α1f1z2+α2f2z+c2=1,β1f2z2+β2f1z+c2=1,α1∂f1/∂z1n1+α2f2z+cm1=1,β1∂f2/∂z1n2+β2f1z+cm2=1, and α1∂f1/∂z12+α2f2z+c2=1,β1∂f2/∂z12+β2f1z+c2=1,α1∂f1/∂z12+α2f2z+c+α3f1z2=1,β1∂f2/∂z12+β2f1z+c+β3f2z2=1, where αj,βjj=1,2,3 are nonzero constants in ℂ and mj,njj=1,2 are positive integers. We obtain several theorems on the existence and the forms of solutions for these systems, which are some improvements and supplements of the previous theorems given by Xu and Cao, Gao, and Liu and Yang. Moreover, we give some examples to explain the existence of solutions for such systems
Nanozymatic activity of Zr-based MOFs: Tuning the coordinatively unsaturated metal sites for enhancing hydrolytic activity toward peptide bonds
No full textObjective: To develop efficient and stable artificial proteases and investigate the relationship between coordinatively unsaturated metal sites and hydrolysis activity of peptide bond. Methods: Three zirconium-based metal-organic frameworks （Zr-MOFs） with different coordinatively unsaturated sites （12-connected Zr-MOF, 6-connected Zr-MOF, and 4-connected Zr-MOF） were prepared to modulate protein hydrolase activity. The protein hydrolase activity of three Zr-MOFs was evaluated by the hydrolysis rate of bis-glycopeptide （Gly-Gly） as an indicator. Subsequently, soy protein, surimi protein and casein were hydrolyzed using the best performing protein hydrolase nanoenzymes, and the hydrolysis products were separated using SDS-polyacrylamide gel electrophoresis, and the hydrolysis efficiency of the three proteins by artificial proteases was investigated by staining the separated bands with Komas Brilliant Blue. Results: Among the three Zr-MOFs proteases, the 6-connected Zr-MOF showed the highest hydrolysis （52%） efficiency toward the Gly-Gly. The hydrolysis reaction rate was increased 2.63×103 times compared the uncatalyzed hydrolysis. In addition, the 6-connected Zr-MOF could respectively hydrolyze three commonly proteins in the food industry and had the highest catalytic effect on surimi protein. Conclusion: These results revealed that the ability of Zr-MOF to hydrolyze peptide bonds could be enhanced by tuning the coordinatively unsaturated sites. The study provided a new idea for the application of artificial proteases in food industry
Solvability for a system of Hadamard-type hybrid fractional differential inclusions
No full textIn this article, a new system of Hadamard-type hybrid fractional differential inclusions equipped with Dirichlet boundary conditions was constructed. By virtue of a fixed-point theorem due to B. C. Dhage, (Existence results for neutral functional differential inclusions in Banach algebras, Nonlinear Anal. 64 (2006), no. 6, 1290–1306, doi: https://doi.org/10.1016/j.na.2005.06.036), the existence results of solutions for the considered problem are derived in a new norm space for multivalued maps. A numerical example is provided to illustrate our main results
Positive solutions for an impulsive boundary value problem with Caputo fractional derivative
No full textAggregate k Nearest Neighbor Queries in Metric Spaces
No full textAggregate k nearest neighbor (AkNN) queries are useful in many areas, such as multimedia retrieval and resource allocation, to name but a few. Most of existing works on AkNN query only focus on Euclidean space or specific metric space, which employ properties of particular data to accelerate the query. However, due to the complex data types involved and the needs for flexible similarity criteria seen in real applications, properties of particular data cannot be used for general case. Hence, in this paper, we investigate AkNN search in metric spaces, termed as metric AkNN (MAkNN) search, as metric spaces can support any type of data and flexible similarity criteria as long as satisfying triangle inequality. To efficiently answer MAkNN queries, we develop several pruning techniques and corresponding algorithms based on SPB-tree. Extensive experiments using three real data sets verify the efficiency of our MAkNN algorithms
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