Microorganism-mediated, hexadecyltrimethylammonium chloride （CTAC）-directed （MCD） method was employed in this work to synthesize Pd nanoflowers （PdNFs）. Proper Pichia postoris cells （PPCs） dosage, ascorbic ac...Microorganism-mediated, hexadecyltrimethylammonium chloride （CTAC）-directed （MCD） method was employed in this work to synthesize Pd nanoflowers （PdNFs）. Proper Pichia postoris cells （PPCs） dosage, ascorbic acid （AA）, Pd（N03）2 and CrAC concentrations were essential for the growth of the PdNFs. The size of the as- synthesized PdNFs could be tuned by adjusting the amount of Pal（N03）2 solution and dosage of PPCs used. Characterization techniques such as X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy were used to verify the nature of the PdNFs. Finally the PdNF/PPC nanocomposites were immobilized onto TiO2 supports to obtain bio-PdNF/Ti02 catalysts which showed excellent catalytic activity for CO oxidation, obtaining 100%; conversion at 100 ℃ and remaining stable over a period of 52 h of reaction time. @ 2015 The Chemical Industry and Engineering Sodety of China, and Chemical Industry Press. All rights reserved.展开更多
In order to investigate the influening factors of organic modification procedure and find out connections between organic modification and the properties of bentonite greases, organic montmorillonite(OMMT) thickeners ...In order to investigate the influening factors of organic modification procedure and find out connections between organic modification and the properties of bentonite greases, organic montmorillonite(OMMT) thickeners with different surfactant dosages and constituents were synthesized through intercalation reaction between sodium montmorillonite(NaM MT) and quaternary ammonium surfactants in aqueous solvents. The lubricating greases were prepared with the resulting organoclays, while the penetration and oil separation of lubricating greases were evaluated, respectively. The surface modification process of montmorillonite(MMT) was analyzed and the thickening mechanism of OMMT was discussed in this study. The experimental results showed that, with an increasing amount of surfactant, the basal spacing between the clay platelets was increasing and the structure of modifier molecules layer in the interlayer was changing from lateral bilayer to paraffin-type bilayer. The optimal properties of lubricating greases were achieved, when the structure of surfactant molecules loaded in the interlayer was the paraffin-type monolayer, which meant that the dosage of modifier was equal to 120—140 mmol/(100g). Meanwhile, it was found that the thickening performance, colloid stability, anti-wear and friction-reducing performance of lubricating greases were improved, when the surfactants were mixed with octadecyl trimethyl ammonium chloride(OTAC) and hexadecyl trimethyl ammonium chloride(HTAC). And the optimum mole ratio of two surfactants is was 1:1.展开更多
In this study, a new control strategy for turbulent drag reduction involving ventilated cavitation is proposed. The configurational and hydrodynamic characteristics of ventilated cavities influenced by turbulent drag-...In this study, a new control strategy for turbulent drag reduction involving ventilated cavitation is proposed. The configurational and hydrodynamic characteristics of ventilated cavities influenced by turbulent drag-reducing additives were experimentally studied in water tunnel. The test model was fixed in the water tunnel by a strut in the aft-part. Aqueous solutions of CTAC/Na Sal(cetyltrimethyl ammonium chloride/sodium salicylate) with weight concentrations of 100, 200, 400 and 600 ppm(part per million), respectively, were injected into the ventilated air cavity from the edge of the cavitator with accurate control by an injection pump. The cavity configurations were recorded by a high-speed CCD camera. The hydrodynamic characteristics of the test model were measured by a six-component balance. Experimental results show that, within the presently tested cases, the lengths of cavity influenced by drag-reducing solution are smaller than normal condition(ventilated cavity) in water, but the asymmetry of the cavity is improved. The drag resisted by the test model is reduced dramatically(the maximum drag reduction can reach to 80%) and the re-entrant jet is more complex after the CTAC solution is injected into the cavity. Turbulent drag-reducing additives have the potential in enhancement of supercavitating asymmetry and further drag reduction.展开更多
Surface and grain boundary defects in halide perovskite solar cells are highly detrimental,reducing efficiencies and stabilities.Widespread halide anion and organic cation defects usually aggravate ion diffusion and m...Surface and grain boundary defects in halide perovskite solar cells are highly detrimental,reducing efficiencies and stabilities.Widespread halide anion and organic cation defects usually aggravate ion diffusion and material degradation on the surfaces and at the grain boundaries of perovskite films.In this study,we employ an in-situ green method utilizing nontoxic cetyltrimethylammonium chloride(CTAC)and isopropanol(IPA)as anti-solvents to effectively passivate both surface and grain boundary defects in hybrid perovskites.Anion vacancies can be readily passivated by the chloride group due to its high electronegativity,and cation defects can be synchronously passivated by the more stable cetyltrimethylammonium group.The results show that the charge trap density was significantly reduced,while the carrier recombination lifetime was markedly extended.As a result,the power conversion efficiency of the cell can reach 23.4%with this in-situ green method.In addition,the device retains 85%of its original power conversion efficiency after 600 h of operation under illumination,showing that the stability of perovskite solar cells is improved with this in-situ passivation strategy.This work may provide a green and effective route to improve both the stability and efficiency of perovskite solar cells.展开更多
基金Supported by the National Natural Science Foundation of China （21106117, 21036004）.
文摘Microorganism-mediated, hexadecyltrimethylammonium chloride （CTAC）-directed （MCD） method was employed in this work to synthesize Pd nanoflowers （PdNFs）. Proper Pichia postoris cells （PPCs） dosage, ascorbic acid （AA）, Pd（N03）2 and CrAC concentrations were essential for the growth of the PdNFs. The size of the as- synthesized PdNFs could be tuned by adjusting the amount of Pal（N03）2 solution and dosage of PPCs used. Characterization techniques such as X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy were used to verify the nature of the PdNFs. Finally the PdNF/PPC nanocomposites were immobilized onto TiO2 supports to obtain bio-PdNF/Ti02 catalysts which showed excellent catalytic activity for CO oxidation, obtaining 100%; conversion at 100 ℃ and remaining stable over a period of 52 h of reaction time. @ 2015 The Chemical Industry and Engineering Sodety of China, and Chemical Industry Press. All rights reserved.
基金financially supported by the Chongqing Construction Project of Innovation Teams in Colleges and Universities-Petroleum Products Application Engineering and Technology(Project No.KJTD201342)the Chongqing Project of Innovation Research by Postgraduates(Project No.CYB16130)
文摘In order to investigate the influening factors of organic modification procedure and find out connections between organic modification and the properties of bentonite greases, organic montmorillonite(OMMT) thickeners with different surfactant dosages and constituents were synthesized through intercalation reaction between sodium montmorillonite(NaM MT) and quaternary ammonium surfactants in aqueous solvents. The lubricating greases were prepared with the resulting organoclays, while the penetration and oil separation of lubricating greases were evaluated, respectively. The surface modification process of montmorillonite(MMT) was analyzed and the thickening mechanism of OMMT was discussed in this study. The experimental results showed that, with an increasing amount of surfactant, the basal spacing between the clay platelets was increasing and the structure of modifier molecules layer in the interlayer was changing from lateral bilayer to paraffin-type bilayer. The optimal properties of lubricating greases were achieved, when the structure of surfactant molecules loaded in the interlayer was the paraffin-type monolayer, which meant that the dosage of modifier was equal to 120—140 mmol/(100g). Meanwhile, it was found that the thickening performance, colloid stability, anti-wear and friction-reducing performance of lubricating greases were improved, when the surfactants were mixed with octadecyl trimethyl ammonium chloride(OTAC) and hexadecyl trimethyl ammonium chloride(HTAC). And the optimum mole ratio of two surfactants is was 1:1.
基金supported by National Natural Science Foundation of China(Grant No.51276046)
文摘In this study, a new control strategy for turbulent drag reduction involving ventilated cavitation is proposed. The configurational and hydrodynamic characteristics of ventilated cavities influenced by turbulent drag-reducing additives were experimentally studied in water tunnel. The test model was fixed in the water tunnel by a strut in the aft-part. Aqueous solutions of CTAC/Na Sal(cetyltrimethyl ammonium chloride/sodium salicylate) with weight concentrations of 100, 200, 400 and 600 ppm(part per million), respectively, were injected into the ventilated air cavity from the edge of the cavitator with accurate control by an injection pump. The cavity configurations were recorded by a high-speed CCD camera. The hydrodynamic characteristics of the test model were measured by a six-component balance. Experimental results show that, within the presently tested cases, the lengths of cavity influenced by drag-reducing solution are smaller than normal condition(ventilated cavity) in water, but the asymmetry of the cavity is improved. The drag resisted by the test model is reduced dramatically(the maximum drag reduction can reach to 80%) and the re-entrant jet is more complex after the CTAC solution is injected into the cavity. Turbulent drag-reducing additives have the potential in enhancement of supercavitating asymmetry and further drag reduction.
基金the National Key Research and Development Program of China(2016YFA0202400 and 2016YFA0202404)the National Natural Science Foundation of China(61904076 and U19A2089)+3 种基金the Natural Science Foundation of Guangdong Province(2020A1515010980 and 2019B1515120083)the Peacock Team Project funding from the Shenzhen Science and Technology Innovation Committee(KQTD2015033110182370)the Shenzhen Engineering R&D Center for Flexible Solar Cells Project funding from Shenzhen Development and Reform Committee(2019-126)the GuangdongHong Kong-Macao Joint Laboratory(2019B121205001)。
文摘Surface and grain boundary defects in halide perovskite solar cells are highly detrimental,reducing efficiencies and stabilities.Widespread halide anion and organic cation defects usually aggravate ion diffusion and material degradation on the surfaces and at the grain boundaries of perovskite films.In this study,we employ an in-situ green method utilizing nontoxic cetyltrimethylammonium chloride(CTAC)and isopropanol(IPA)as anti-solvents to effectively passivate both surface and grain boundary defects in hybrid perovskites.Anion vacancies can be readily passivated by the chloride group due to its high electronegativity,and cation defects can be synchronously passivated by the more stable cetyltrimethylammonium group.The results show that the charge trap density was significantly reduced,while the carrier recombination lifetime was markedly extended.As a result,the power conversion efficiency of the cell can reach 23.4%with this in-situ green method.In addition,the device retains 85%of its original power conversion efficiency after 600 h of operation under illumination,showing that the stability of perovskite solar cells is improved with this in-situ passivation strategy.This work may provide a green and effective route to improve both the stability and efficiency of perovskite solar cells.
