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991.
Jin Xu Tingting Zang Ding Du Sandeep Kumar Moolchand Sharma Rahul Vaish 《Journal of the American Ceramic Society》2021,104(4):1661-1668
The BaTiO3 powder was prepared via a solid-state reaction route. It was studied for the degradation of bacterial cells, dye, and pharmaceuticals waste using ultrasonically driven piezocatalytic effect. The bacterial catalytic behavior of poled BaTiO3 was remarkably increased during ultrasonication (10% E coli survival in 60 minutes). The structural damages were illustrated using scanning electron micrographs of bacterial cells which demonstrated morphological manifestations under different conditions. Methylene blue (MB dye), ciprofloxacin and diclofenac were also cleaned using the piezocatalytic effect associated with the poled BaTiO3 powder. Around 92, 85, and 78% of degradations were observed within 150 minutes duration for methylene blue, ciprofloxacin, and diclofenac, respectively. 相似文献
992.
Bioremediation strategies have been applied to clean up petroleum hydrocarbon (PHC) impacted sites. Introducing PHC degrading microorganisms (bioaugmentation) and enhancing the in‐situ nutrients availability (biostimulation) are widely used strategies. These strategies can be combined to lead to a better bioremediation performance. In this work, Pseudomonas fluorescens was isolated from a PHC impacted site. Through a 23 factorial design plan, the effect of various combinations of nitrate, sulphate, and phosphate ions on the PHC bioremediation performance by P. fluorescens was investigated using catechol, an essential metabolic intermediate of BTEX degradation, as the sole carbon source. The maximum specific catechol degradation rate was chosen as the response to evaluate the catechol bioremediation performance. The ANOVA results indicated that the presence of nitrate ions alone lowered the maximum specific catechol degradation rate, which can be explained by the accumulation of nitrites and ammonia during the denitrification process by P. fluorescens. It was noted that dosing sulphate ions alone did not affect the bioremediation performance, which indicates P. fluorescens can grow in a sulphur‐limited environment. In contrast, the presence of sulphate and nitrate ions together can lead to a higher specific catechol degradation rate. This may be caused by the presence of sulphate that can suppress the production of nitrites. The importance of phosphate ions on catechol biodegradation was investigated. The absence of phosphate led to incomplete biodegradation. Introducing phosphate ions can accelerate catechol degradation, which can be explained by the secretion of organic acids. 相似文献
993.
The flame retardant polypropylene containing the micro-envelope core-shell structure flame retardant, which encapsulated ammonium polyphosphate into melamine-formaldehyde resin and sodium silicate through in situ polymerization was prepared with polyamide 6, added as a carbon-forming agent. The composition of ammonium polyphosphate, encapsulated ammonium polyphosphate with melamine-formaldehyde resin and the micro-envelope core-shell structure flame retardant were characterized. The fire safety and thermal stability were investigated and showed an improvement including limiting oxygen index, thermogravimetric analysis, vertical burning tests, and microscale combustion calorimeter. The burned compounds were also studied to confirm the burning mechanism. The results showed the flame retardant performance had been greatly improved, while polyamide 6 had better char-forming effect. Besides, the water solubility of flame retardants and their influence on the mechanical properties of polypropylene were also investigated. The results on the effects of additives demonstrated a high efficiency flame retardant to polypropylene. A core-shell flame retardant that sodium silicate and melamine-formaldehyde resin-coated ammonium polyphosphate had been constructed. The effect of the built flame retardant system on the combustion performance of polypropylene was studied from the mechanism and performance. The LOI of the most flame retardant polypropylene reached 28.6%, and UL-94 reached the V-0 level. 相似文献
994.
Junfeng Yue Xuejiao Fu Jun Lu Shuidong Zhang Dong Li Yi He Quan Wei Changhua Liu Lin Gan Ishak Ahmad Jin Huang 《应用聚合物科学杂志》2021,138(45):51330
Sustainable development strategy has aroused a great interest in biomass resources as alternative raw materials. A kind of biomass-derived poly(butylene succinate) (PBS), has been developed as porous foams to reduce resource exhaustion and meet lightweight demands. For fire-safety in-service, graphene oxide (GO) was functionalized by 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) to combine flame-retardant elements and heat-barrier function. Hence, a very low loading level of P-containing GO as only 5 wt% could reduce peak heat release rate (pHRR) and total heat release (THR) of PBS-based foams by 58.5% and 22.3%, respectively. Meanwhile, N-/P-doped mesoporous char with a specific surface area of 136 m2/g, which derived from combustion of flame-retardant foaming PBS, contributes to a potential of energy storage applications in the capacitor or the anode of Li-ion battery with long-term stability. Overall, the sustainability of bio-based polyester could integrate lightweight of foaming, and be extended to utilization after use via facile combustion inspired by flame-retardancy design. 相似文献
995.
Nouman Ali Shah Yue Ren Ri-Tong Lan Jia-Cheng Lv Rizwan M. Gul Peng-Fei Tan Shishu Huang Lin Tan Jia-Zhuang Xu Zhong-Ming Li 《应用聚合物科学杂志》2021,138(43):51261
Highly crosslinked ultrahigh molecular weight polyethylene (UHMWPE) stabilized by vitamin E (VE) is widely applied in artificial joints as the bearings. Despite the approval, there is a discord that VE lowers the crosslinking efficiency, limiting its use at high concentration. In this work, we aim to obtain highly crosslinked and oxidation resistant UHMWPE through the conjunction of tea polyphenol and chemical crosslinking. We hypothesized that highly incorporated tea polyphenol with multiple reactive sites can ameliorate crosslinking efficiency of chemical crosslinked UHMWPE in comparison to VE. Epigallocatechin gallate (EGCG) as representative tea polyphenol was incorporated into UHMWPE at high concentration (2–8 wt%), followed by chemical crosslinking with 2 wt% organic peroxide. Unlike VE/UHMWPE blends as the control, chemical crosslinking achieved an increasing trend in crosslink density of EGCG/UHMWPE blends with increasing antioxidant concentration. High concentration of EGCG also enhanced the oxidation stability of UHMWPE. Intriguingly, EGCG endowed UHMWPE with an excellent antimicrobial property, which was inefficient in VE/UHMWPE. Cell viability was hardly affected by the high loaded antioxidant and peroxide. The chemically crosslinked UHMWPE blended with EGCG is proved to be a reasonable, cost effective and realistic alternative for use in artificial joints. 相似文献
996.
以异佛尔酮二异氰酸酯( IPDI)、六亚甲基二异氰酸酯(HDI)和聚己二酸 1,4-丁二醇酯二醇( PBA)为主要原料制备系列水性聚氨酯乳液( WPU)。采用红外光谱仪、差式扫描量热仪、 X-射线衍射仪、电子拉力机等对 WPU进行结构表征;为了从聚集状态上对聚氨酯结晶性有更深层次的探究,对 WPU进行了定伸情况下的测试。结果显示:随着硬段含量的增加,硬段 -软段间的氢键相互作用减小,微相分离程度增加,结晶性能降低;随着伸长率的增加,氢键相互作用和结晶性能都表现出先减小后增大的趋势。当硬段含量为 14. 73%时,聚氨酯胶膜拉伸强度达到 40. 11 MPa,剥离强度为 93. 7 N/(25 mm)。 相似文献
997.
Kui Liu Minjie Wang Hongxia Li Danyang Zhao Yifei Jin 《Polymer Engineering and Science》2021,61(6):1864-1881
The swelling behavior in micro-extrusion has a significant effect on the dimensional and shape accuracy of microproducts. In this study, the effect of characteristic scale, defined as the gap of die land in an annular micro-extrusion die, on the extrudate swelling behavior of viscoelastic melt is analyzed through numerical simulations and micro-extrusion experiments. The results show that the swelling behavior displays an obvious dependence on the characteristic scale. An increase in the characteristic scale reduces the swell ratio and retards the process to reach the equilibrium state. In contrast, a decrease in the characteristic scale results in a larger magnitude of change in velocity field and faster relaxation development of stress field. The location of the maximum velocity layer for the laminar flow gradually deviates from the geometric center of channel toward the wall of mandrel with the increase in the characteristic scale. Moreover, an increase in the flow rate results in a larger swell ratio for a constant characteristic scale. The elastic effect plays a more dominant role than the viscous effect in determining the viscoelastic swell behavior. It is imperative to consider the complicated swelling behavior and remarkable viscoelastic effect simultaneously in micro-extrusion process. 相似文献
998.
输出并联型双有源全桥(dual-active-bridge,DAB)DC-DC变换器具备电气隔离、模块化扩展简单、高变比升降压及功率双向传输等优势,近年来得到国内外专家学者的广泛关注。首先,分析和归纳该类变换器功率平衡的典型控制方案,并从动态特性、模块化程度、传感器数量等方面,对不同控制方案下的研究策略进行多方面对比分析;然后,基于DAB变换器效率和动态性能优化方法,从多模块角度出发,分析组合系统功率平衡与DAB变换器性能优化相结合的一些典型混合控制策略,并从工程角度给出混合控制其他衍生思路及控制策略选取时,需考虑的实际因素;最后,从开关、桥臂、模块和拓扑等方向,对输出并联DAB变换器的容错控制方案进行详细概述并总结全文。 相似文献
999.
高性能、高安全储能电池的迫切需求加速了橄榄石型高电压正极材料的研究步伐。为了改善高电压磷酸钴锂(LiCoPO4)的综合电化学性能,采用溶剂热法研究了溶剂比、过渡元素(Fe、Mn)单掺杂和双掺杂(掺杂元素总量占10%)对正极材料形貌、尺寸、反位缺陷和电化学性能的影响。结果表明,当溶剂比为2.3时,未掺杂LiCoPO4在0.1C下表现出163.1 mAh·g-1的最高理论比容量;双掺杂LiCo0.9Mn0.05Fe0.05PO4正极材料具有突出的循环性能,在0.5C电流密度下,循环100圈后的容量保持率为78.9%,循环稳定性得到明显改善。 相似文献
1000.