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201 results on '"Yang, Wen-long"'

4. Flame retardant performance of nano-Sb2O3/BEO/PP composites

Author

XU Jian-lin, LIU Xiao-qi, YANG Wen-long, NIU Lei, and ZHAO Jin-qiang

Subjects
polypropylene, nano-Sb2O3, brominated epoxy resin, flame retardant performance, Materials of engineering and construction. Mechanics of materials, TA401-492
Abstract

To improve flame retardant properties of polypropylene,the brominated epoxy resin (BEO) and nano-Sb2O3 were added into polypropylene by using a high energy ball milling technique. Flame retardant properties of polypropylene composites were evaluated by UL94 vertical combustion tests and limit oxygen index (LOI). The surface morphology of combustion products of composites was characterized by scanning electron microscopy(SEM) and the flame-retardant mechanism of flame retardant additives acting on the polymer matrix was studied by using thermo gravimetric analysis(TGA) and Fourier transform infrared (FT-IR) spectroscopy. The results show that the reaction between modified nano-Sb2O3 and BEO can prolong residence of the halogens in the combustion area, resulting in more hydroxyl and hydrogen radicals are replaced by the bromine radicals. When the content of modified nano-Sb2O3 is 7% (mass fraction, the same below) and that of BEO is 21%, the nano-Sb2O3/BEO/PP composite has excellent flame retardant performance with 28.6% of LOI value and V-0 of UL94 grade of vertical combustion.

Published
2019
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5. Relation between three-qubit entanglement invariants and two-qubit concurrence

Author

Yang, Wen-Long and Chen, Jing-Ling

Subjects
Quantum Physics
Abstract

In this Brief Report we show the relation between three-qubit entanglement invariants and two-qubit concurrence with the help of projective measurements. How to use these invariants to represent the entanglement property of three-qubit pure states is also investigated., Comment: 4 pages, 2 figures

Published
2007
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6. Berry's phase for coherent states of Landau levels

Author

Yang, Wen-Long and Chen, Jing-Ling

Subjects
Quantum Physics
Abstract

The Berry phases for coherent states and squeezed coherent states of Landau levels are calculated. Coherent states of Landau levels are interpreted as a result of a magnetic flux moved adiabatically from infinity to a finite place on the plane. The Abelian Berry phase for coherent states of Landau levels is an analog of the Aharonov- Bohm effect. Moreover, the non-Abelian Berry phase is calculated for the adiabatic evolution of the magnetic field B., Comment: 4 pages, 1 figure

Published
2007
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10. Effect of Sb2O3 Modified by Various Surface Active Agents on Flame Retardant Properties of PVC Composite

Author

XU Jian-lin, ZHOU Sheng-gang, NIU Lei, YANG Wen-long, WANG Cheng-cheng, and WEN Chen

Subjects
surface active agent, Sb2O3, PVC, composite, flame retardant property, Materials of engineering and construction. Mechanics of materials, TA401-492
Abstract

Sb2O3 powders were prepared by high energy ball milling using polyethyleneglycol-6000,sodium dodecyl sulfate and OP-10 to modify the surface properties of the powder. The influence of Sb2O3 powders modified by various surface active agents on flame retardant properties of PVC composite materials was studied. The phase composition, morphology and the average particle size of the powders were characterized by XRD and TEM. The particle distribution and flame retardant properties of Sb2O3/PVC composite materials were studied by EDS, limiting oxygen index instrument and vertical burning test. The results show that nanometer Sb2O3 has good dispersion in the PVC matrix because of the higher space steric effect of organic film on the surface of nanometer Sb2O3 when polyethyleneglycol-6000 was used as the surface active agent. While the content of nanometer Sb2O3 is 1.26% in the PVC composite material, the oxygen index of the composite material is 27.1% and the composite material reaches fire retardant grade. Using sodium dodecyl sulfate and OP-10 as surface dispersants, the surface of Sb2O3 powders can not be coated completely. The particle size of Sb2O3 powders are 100nm and 150nm, respectively, The Sb2O3 powders have poor dispersion in the PVC matrix, and even some agglomerating phenomena took place. The oxygen index of Sb2O3/PVC composite materials are 24.7% and 25.3%, respectively, containing 1.26% Sb2O3 powders in Sb2O3/PVC composite material. The materials don't achieve flame retardant level.

Published
2016
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27. Effects of Forming Processes on Microstructures and Mechanical Properties of A356 Aluminum Alloy Prepared by Self-inoculation Method

Author

Li Ming, Li Yuan-dong, Wang Zong-gang, Yang Wen-long, and Zhang Yu

Subjects
Materials science, A356 aluminum alloy, Alloy, 02 engineering and technology, engineering.material, 01 natural sciences, Isothermal process, semisolid, 0103 physical sciences, General Materials Science, Lamellar structure, eutectic structure, Composite material, Materials of engineering and construction. Mechanics of materials, Eutectic system, 010302 applied physics, Mechanical Engineering, Forming processes, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Microstructure, equipment and supplies, Mechanics of Materials, self-inoculation method, TA401-492, engineering, Slurry, Particle, 0210 nano-technology, solidification behavior
Abstract

Semisolid slurry of A356 aluminum alloy was prepared by Self-Inoculation Method (SIM), and the microstructures and solidification behavior of rheo-forming process in different forming processes were researched. The results indicate that semisolid slurry of A356 aluminum alloy can be prepared by Self-Inoculation Method at 600ºC. Primary α-Al particles with fine and spherical morphology are uniformly distributed when the isothermal holding time of slurry is 3 min. The different forming processes for semisolid rheo-forming can be regarded as the effect of cooling rate on rheo-forming. The primary particle sizes and shape factors are gradually increasing with the increase of cooling rate. The sizes of secondary particles are gradually increasing with the decrease of cooling rate, and the amount of secondary particles in the same areas are gradually decreasing with the decrease of cooling rate. The morphologies of eutectic Si are gradually coarsening from fibrous to needle-like in different forming processes, while the sizes and the lamellar spacing of the eutectic Si are gradually increasing with the decrease of cooling rate. The mechanical properties of the semisolid forming components are gradually increasing with the increase of cooling rate and forming pressure.

Published
2019

38. Bioinformatics of a Novel Nitrile Hydratase Gene Cluster of the N2-Fixing Bacterium Microvirga flocculansCGMCC 1.16731 and Characterization of the Enzyme

Author

Zhao, Yun-Xiu, Yang, Wen-Long, Guo, Ling, Jiang, Huo-Yong, Cheng, Xi, and Dai, Yi-Jun

Abstract

Microvirga flocculansCGMCC 1.16731 can degrade many cyano group-containing neonicotinoid insecticides. Here, its genome was sequenced, and a novel nitrile hydratase gene cluster was discovered in a plasmid. The NHase gene cluster (pnhF) has gene structure β-subunit 1, α-subunit, and β-subunit 2, which is different from previously reported NHase gene structures. Phylogenetic analysis of α-subunits indicated that NHases containing the three subunit (β1αβ2) structure are independent from NHases containing two subunits (αβ). pnhFwas successfully expressed in Escherichia coli, and the purified PnhF could convert the nitrile-containing insecticide flonicamid to N-(4-trifluoromethylnicotinoyl)glycinamide. The enzymatic properties of PnhF were investigated using flonicamid as a substrate. Homology models revealed that amino acid residue β1-Glu56 may strongly affect the catalytic activity of PnhF. This study expands our understanding of the structures and functions of NHases and the enzymatic mechanism of the environmental fate of flonicamid.

Published
2020
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39. Sulfoxaflor Degraded by Aminobactersp. CGMCC 1.17253 through Hydration Pathway Mediated by Nitrile Hydratase

Author

Yang, Wen-Long, Dai, Zhi-Ling, Cheng, Xi, Guo, Ling, Fan, Zhi-Xia, Ge, Feng, and Dai, Yi-Jun

Abstract

Sulfoxaflor, a sulfoximine insecticide, could efficiently control many insect pests of sap-feeding. Microbial degradation of sulfoxaflor and the enzymatic mechanism involved have not been studied to date. A bacterial isolate JW2 that transforms sulfoxaflor to X11719474 was isolated and identified as Aminobactersp. CGMCC 1.17253. Both the recombinant Escherichia colistrain harboring the Aminobactersp. CGMCC 1.17253 nitrile hydratase (NHase) gene and the pure NHase acquired sulfoxaflor-degrading ability. Aminobactersp. CGMCC 1.17253 NHase is a typical cobalt-containing NHase content of subunit α, subunit β, and an accessory protein, and the three-dimensional homology model of NHase was built. Substrate specificity tests showed that NHase catalyzed the conversion of acetamiprid, thiacloprid, indolyl-3-acetonitrile, 3-cyanopyridine, and benzonitrile into their corresponding amides, indicating its broad substrate specificity. This is the first report of the pure bacteria degradation of the sulfoxaflor residual in the environment and reveals the enzymatic mechanism mediated by Aminobactersp. CGMCC 1.17253.

Published
2020
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40. Biodegradation of the Insecticide Flonicamid by Alcaligenes faecalisCGMCC 17553 via Hydrolysis and Hydration Pathways Mediated by Nitrilase

Author

Yang, Wen-Long, Guo, Lei-Lei, Dai, Zhi-Ling, Qin, Ruo-Chen, Zhao, Yun-Xiu, and Dai, Yi-Jun

Abstract

Flonicamid (N-cyanomethyl-4-trifluoromethylnicotinamide, FLO), a novel selective systemic pyridinecarboxamide insecticide, effectively controls hemipterous pests. However, microbial degradation of flonicamid, along with the enzymatic mechanism, has not been studied. Here, bacterial isolate PG13, which converts flonicamid into 4-(trifluoromethyl)nicotinol glycine (TFNG) and N-(4-trifluoromethylnicotinoyl)glycinamide (TFNG-AM), was isolated and identified as Alcaligenes faecalisCGMCC 17553. The genome of CGMCC 17553 contained five nitrilases but no nitrile hydratase, and recombinant Escherichia colistrains harboring CGMCC 17553 nitrilase gene nitAor nitDacquired the ability to degrade flonicamid. Purified NitA catalyzed flonicamid into both TFNG and TFNG-AM, indicating dual functionality, while NitD could only produce TFNG-AM. Three-dimensional homology modeling revealed that aromatic amino acid residues in the catalytic pocket affected nitrilase activity. These findings further our understanding of the enzymatic mechanism of flonicamid metabolism in the environment and may help develop a potential bioremediation agent for the elimination of flonicamid contamination.

Published
2024
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43. Hepatitis B surface antigen quantification at hepatitis B e antigen seroconversion predicts virological relapse after the cessation of entecavir treatment in hepatitis B e antigen-positive patients

Author

Qiu, Yuan-wang, primary, Huang, Li-hua, additional, Yang, Wen-long, additional, Wang, Zhen, additional, Zhang, Bo, additional, Li, Yi-guang, additional, Su, Ting-ting, additional, Zhou, Hong-yan, additional, Xu, Wei, additional, Wang, Xue-dong, additional, Dai, Ya-ping, additional, and Gan, Jian-he, additional

Published
2016
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