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Sorption of Perfluorooctane sulfonate(PFOS) including its isomers on hydrargillite as a function of pH,humic substances and Na2SO4

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Journal of Environmental Sciences 2022年第1期34卷 263-272页

作者： jean-noel uwayezu Leo W.Y.Yeung Mattias Bäckström Man-Technology-Environment Research Centre(MTM) Örebro University70182ÖrebroSweden

Perfluorooctane sulfonate(PFOS)is a persistent organic pollutant(POP)and emergent contaminant that are widespread in the *** the mechanisms controlling the distribution of PFOS and its isomers between hydrargillite and the water phase is important in order to study their redistribution and mobility in the *** study investigated the effects of pH,humic acid,fulvic acid and Na_(2)SO_(4) on sorption of PFOS isomers to hydrargillite.A mixture of PFOS isomers was spiked into water and hydrargillite was added to the system and shaken for one day;the system was tested with different aqueous *** of PFOS isomers in the aqueous phase were quantified using an ultra-performance liquid chromatograph coupled to a triple quadrupole mass *** results showed that the distribution coefficients of PFOS isomers were found to be 0.76,0.71,0.93 and 0.90 at pH 6.5,for 3-/4-/5-PFOS,6-/2-PFOS,L-PFOS and total PFOS *** distribution coefficients increased at lower pH and decreased at alkaline *** presence of humic substances(HS)increased the sorption slightly at the environmental pH of 6.5,although a competition effect was observed during acidic conditions.A tendency of PFOS distribution to hydrargillite in the presence of Na_(2)SO_(4) was like its behavior in the presence of HS although the mechanisms behind the sorption were interpreted *** study revealed that L-PFOS was readily sorbed when no other chemicals were added or in 20 mg/L FA or 100 mg/L Na_(2)SO_(4).We suggest that an increase in PFOS sorption in the presence of HS may be due to hydrophobic mechanisms while Na_(2)SO_(4) contributed to increased sorption through ionic strength effects.

关键词： Hydrargillite Perfluorooctane sulfonate Sorption Humic substances Electrostatic,Ionic strength

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Characterization and Modeling of Large-Scale Fading for Radio Propagation in Rwanda

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Communications and Network 2016年第1期8卷 22-30页

作者： uwayezu jean de Dieu Nsengiyumva jean Marie Vianney Faculty of Science and Technology Catholic University of Rwanda Butare Rwanda

Radio links are extensively used for voice and data communications at long distance. We analyze the radio propagation parameters that affect the received signal level on radio links in Rwanda and we determine the best path loss model for prediction of the received signal level. Various models of propagation and the mathematical expressions of path loss are described here in order to come to the prediction of those propagation effects. By analyzing data collected for two links of MTN Rwanda: Gahengeri-Kibungo and Gahengeri-Jali, we find that the best predicting model is the normal distribution.

关键词： Fading Effects Radio Link Design Diffraction Fading Path Loss Large-Scale Fading

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Biphasic Mechanical Properties of in vivo Repaired Cartilage

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Journal of Bionic Engineering 2015年第3期12卷 473-482页

作者： Qin Lian Cheng Chen Marie Chantal uwayezu Weijie Zhang Weiguo Bian Junzhong Wang Zhongmin Jin State Key Laboratory for Manufacturing Systems Engineering Xi 'an Jiaotong University Xi 'an 710054 China Orthopaedics Department First Affiliated Hospital Xi 'an Jiaotong University Xi 'an 710061 China Institute of Medical and Biological Engineering School of Meehanical Engineering University of Leeds Leeds LS2 9JT UK

In the fast growing field of scaffold-based tissue engineering, improvement on the mechanical properties of newly formed tissues, e.g. the repaired cartilage, has always been one of the core issues. Studies on the correlations among scaffold composition, in vivo morphological changes of the construct, and the finite deformation behaviors of new tissues （e.g. creep and stress-relaxation, and equilibrium response）, have attracted increasing interests. In this paper, the correlations between the compressive biphasic mechanical properties （i.e., equilibrium elastic modulus E and permeability coefficient k） of 3D printing scaffold （consisting of collagen and fl-tricalcium phosphate） and the proteoglycans （PGs） concentration of the repaired carti- lages after 24 weeks, 36 weeks and 52 weeks of scaffold implantation were investigated. Results indicated that the repaired cartilage covered the entire cartilage surface of large cylindrical osteochondral defects （10 mm in diameter ~ 15 mm in depth） on the canine trochlea grooves after 24 weeks. The equilibrium elastic modulus of the repaired cartilage reached 22.4% at 24 weeks, 70.3% at 36 weeks, and 93.4% at 52 weeks of the native cartilage, respectively. Meanwhile, the permeability coefficient decreased with time and at 52 weeks was still inferior to that of the native cartilage in one order of magnitude. In addition, the amount of glycosaminoglycans （GAGs） of repaired cartilage increased constantly with time, which at 52 weeks approached to nearly 60% of that of native cartilage. 3D printed scaffolds have potential applications in repairing large-scale cartilage defects.

关键词： biphasic mechanical properties PGs repaired cartilage osteochondral scaffolds 3D printing

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毛刷状ZnO@PVDF复合纳米纤维柔性压电纳米发电机

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电子元件与材料 2023年第2期42卷 173-180页

作者：谈建强李银辉 Emmanuel uwayezu 梁建国李朋伟太原理工大学纳米能源与器件研究中心山西太原030024

采用静电纺丝技术并通过两步低温水热法制备了“毛刷”状的氧化锌(ZnO)@聚偏二氟乙烯(PVDF)复合纳米纤维膜。结果表明,氧化锌纳米棒(ZnO NRs)均匀地径向生长在PVDF纳米纤维的表面,FTIR分析发现ZnO@PVDF复合纳米纤维膜β相含量相比PVDF... 详细信息

采用静电纺丝技术并通过两步低温水热法制备了“毛刷”状的氧化锌(ZnO)@聚偏二氟乙烯(PVDF)复合纳米纤维膜。结果表明,氧化锌纳米棒(ZnO NRs)均匀地径向生长在PVDF纳米纤维的表面,FTIR分析发现ZnO@PVDF复合纳米纤维膜β相含量相比PVDF纳米纤维膜从72.3%提升到85.6%,增加了18.4%。ZnO@PVDF复合压电纳米发电机(PENG)输出电压可达4.9 V,短路电流为293 nA。在外部负载电阻达到13 MΩ时,ZnO@PVDF复合PENG达到最大输出功率0.93μW。ZnO@PVDF复合PENG可以为电容器充电,电容放电时成功点亮LED小灯泡。此外,在5000次的循环敲击测试中,ZnO@PVDF复合PENG具有稳定的输出电压,有望作为无源设备的自供电电源得到广泛应用。

关键词：静电纺丝 ZnO@PVDF 毛刷状纳米纤维压电纳米发电机

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