排序方式: 共有27条查询结果,搜索用时 15 毫秒
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为改善聚偏氟乙烯(PVDF)膜的抗污性能,以聚乙二醇2000接枝的GO/TiO2(PEG/GO/TiO2)纳米复合材料为添加剂,通过非溶剂诱导沉淀相分离法制备了一系列PEG/GO/TiO2/PVDF复合超滤膜。采用FTIR、SEM和接触角测试仪对其结构和形貌进行了表征,采用超滤法评价其纯水通量和抗污性能。结果表明,当PEG/GO/TiO2纳米复合材料质量分数为0.60%时,制备的PEG/GO/TiO2/PVDF复合超滤膜(记为0.60%PEG/GO/TiO2/PVDF)表现出最佳的亲水性和抗污性能,其接触角比PVDF膜下降8.2°,总孔隙率增加13.40%,PEG/GO/TiO2纳米复合材料在PVDF膜中分散较均匀。在0.08 MPa的工作压力下,0.60%PEG/GO/TiO2/PVDF的纯水通量高达282.44 L/(m2·h),对腐植酸溶液的过滤通量为131.96 L/(m2... 相似文献
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为提高系统产水性能并降低内部结垢,提出一种由非跟踪复合抛物面聚光器加热导热油至100 ℃以上作为供能热源,采用喷雾辅助闪蒸的海水淡化系统。实验研究实际天气中,不同太阳辐照度下进水口温度、进水流量对系统产淡水性能的影响。采用密封压力桶可将进水口温度升至沸点以上,最高可达123 ℃。太阳辐照度波动较大时,进水口温度保持稳定,系统可稳定运行。进水口温度对产水速率影响显著,平均进水口温度从100 ℃升至120 ℃时,产水速率提高47.61%。当进水流量为50 kg/h,压力维持在0.045 MPa时,系统产水速率最大,日累计淡水产量可达11.14 kg/(d·m2),小时效率为81.45%,单级生产率为9.15%。 相似文献
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《Journal of power sources》2004,136(1):88-98
Lithium manganate spinel is extensively studied as a positive electrode in lithium ion rechargeable batteries. Growth of nano-size cathode particles is proposed to improve the rate capabilities of these cathode materials. It remains controversial if the particle size in the nano-range (as compared to the conventional micrometer size particles of these materials) has any appreciable influence on the discharge capacity, rate capabilities, and cycleability of these materials. In the 4 V range, especially at slightly elevated temperature, lithium manganate exhibits capacity fading though the underlying mechanism for such fading is not yet clear. In the present work, we have successfully prepared nano-crystalline lithium manganate spinel powder by an acetate base solution route. Though the discharge capacity of these nano-crystalline cathodes was equivalent to their microcrystalline counterpart, these exhibited capacity fading in the 4 V range. Through a combined X-ray diffraction, micro-Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) analyses, we correlated the observed capacity fading with the onset of Jahn–Teller (J–T) distortion toward the end of the discharge in the cut-off limit between 4.2 and 3.4 V. It was postulated that if J–T distortion is the dominant fading mechanism of these nano-crystalline cathodes then by increasing the average oxidation state of the Mn ions in a virgin lithium manganate cathode, the onset of such distortion towards the end of the discharge could be delayed, and therefore, the cycleability of these cathodes could be improved. By synthesizing lithium and aluminum ion co-doped lithium manganate particles, we could increase the average oxidation state of the Mn ions in the virgin electrodes. Indeed, the cycleability of these co-doped cathodes was dramatically improved which supports our postulation. The doping contents of lithium and aluminum, however, should be further optimized to further increase the discharge capacity of these modified cathodes. 相似文献
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In recent years, tremendous progresses have been achieved for solution processed organic solar cells (OSCs). The strategy of adding a third component to fabricate ternary solar cells has emerged as an effective method to enhance the power conversion efficiency (PCE) of devices. Furthermore, small molecules feature as lower viscosity and excellent repeatability which facilitate the effective morphology control during fabrication process for enhanced photovoltaic performance. Herein, we report a series of ternary solar cells based on a liquid crystal molecule BTR and two electron acceptors of PC71BM and Y6. These molecules show complementary absorption to broaden spectra coverage and form energy levels cascade for efficient charge transfer. Meanwhile, thanks to the improved molecular packing and formed efficient charge transport network in the ternary blend film, the optimal ternary device possesses the improved charge dynamics and suppressed charge recombination. Thus, ternary solar cells deliver the highest PCE of 11.82% with simultaneously enhanced parameters of JSC, VOC and FF. This finding further illustrates the important roles of synergistic effect of fullerenes and non-fullerene acceptors in fabricating highly efficient ternary solar cells. 相似文献
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实验室保藏的一株产脂肪酶基因工程菌X12-5,经过摇瓶发酵,测得酶活力为65U/mL。为进一步提高酶活力,应用于工业生产,将其进行上罐(180L)发酵。大规模发酵后,酶活高达220000U/g,实现了脂肪酶的高效表达。对其酶学性质研究表明,最适温度和pH分别为45℃和7.0;pH在4.0~7.0,温度在50℃以下酶活相对稳定;Mg2+、Mn2+、Ca2+对酶活有明显促进作用。由该脂肪酶的酶学性质初步判断其在制革工业上具有潜在的应用价值。 相似文献
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To further elevate the power conversion efficiency (PCE) of organic solar cells (OSCs), ternary strategy is one of the most efficient methods via simply incorporating a suitable third component. Here, a nonfullerene small molecule acceptor MOITIC was incorporated into the state-of-art PM6:Y6 binary system to further enhance the photovoltaic performance. Detailed investigation revealed that MOITIC exhibited a good miscibility and compatibility with Y6, forming alloy-like acceptors in the ternary blends. The alloy-like phase promoted the phase separation and optimized the morphology of ternary blend, which afforded higher and more balanced carrier mobility and reduced charge recombination in devices. Moreover, the larger energy offset between PM6 and MOITIC:Y6 acceptor alloy is beneficial to enhance open-circuit voltage (Voc) of corresponding devices. As a consequence, the optimized ternary OSC (PM6:Y6:MOITIC = 1:1:0.1) showed a significantly increased PCE of 17.1% with simultaneously enhanced Voc of 0.882 V, short-circuit current density (Jsc) of 25.6 mA cm−2, and fill factor (FF) of 75.7%, which has about 9% enhancement compared to the control binary PM6:Y6 (15.7%). In addition, the optimized ternary device exhibited better stability. This work indicates that ternary strategy via combining two compatible small molecule acceptors is effective to simultaneously improve the efficiency and stability of OSCs. 相似文献
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《Carbon》2013
Adsorption of 1,2,4-trichlorobenzene (TCB), 2,4,6-trichlorophenol (TCP), 2-naphthol and naphthalene (NAPH) on graphene (G) and graphene oxide (GO) was investigated using a batch equilibration method and micro-Fourier transform infrared spectroscopy. All adsorption isotherms of four aromatics on G and GO were nonlinear, indicating that except for hydrophobic interaction, some specific interactions were involved in adsorption. For G, four aromatics had similar adsorption capacity at pH 5.0 in despite of their different chemical properties. A series of pH-dependent experimental results showed that 2-naphthol had higher adsorption capacity on G at alkaline pH than that at acidic pH. Theoretical calculation ascribed this to higher π-electron density of anionic 2-naphthol than that of neutral 2-naphthol, which facilitated the π–π interaction formation with G. For GO, the adsorption affinity of four aromatics increased in the order: NAPH < TCB < TCP < 2-naphthol. FTIR results revealed that TCB, TCP and 2-naphthol were adsorbed on G mainly via π–π interaction. In contrast, high adsorption of TCP and 2-naphthol on GO was attributed to the formation of H-bonding between hydroxyl groups of TCP and 2-naphthol and O-containing functional groups on GO. 相似文献