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41.
42.
Fang J Kelarakis A Lin YW Kang CY Yang MH Cheng CL Wang Y Giannelis EP Tsai LD 《Physical chemistry chemical physics : PCCP》2011,13(32):14457-14461
We report a simple, scalable approach to improve the interfacial characteristics and, thereby, the performance of commonly used polyolefin based battery separators. The nanoparticle-coated separators are synthesized by first plasma treating the membrane in oxygen to create surface anchoring groups followed by immersion into a dispersion of positively charged SiO(2) nanoparticles. The process leads to nanoparticles electrostatically adsorbed not only onto the exterior of the surface but also inside the pores of the membrane. The thickness and depth of the coatings can be fine-tuned by controlling the ζ-potential of the nanoparticles. The membranes show improved wetting to common battery electrolytes such as propylene carbonate. Cells based on the nanoparticle-coated membranes are operable even in a simple mixture of EC/PC. In contrast, an identical cell based on the pristine, untreated membrane fails to be charged even after addition of a surfactant to improve electrolyte wetting. When evaluated in a Li-ion cell using an EC/PC/DEC/VC electrolyte mixture, the nanoparticle-coated separator retains 92% of its charge capacity after 100 cycles compared to 80 and 77% for the plasma only treated and pristine membrane, respectively. 相似文献
43.
Tawfiq NasrAllah Solne Savourey Jean‐Claude Berthet Emmanuel Nicolas Thibault Cantat 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(32):11000-11003
The first iron catalysts able to promote the formal insertion of CO into the C?N bond of amines are reported. Using low‐valent iron complexes, including K2[Fe(CO)4], amides are formed from aromatic and aliphatic amines, in the presence of an iodoalkane promoter. Inorganic Lewis acids, such as AlCl3 and Nd(OTf)3, have a positive influence on the catalytic activity of the iron salts, enabling the carbonylation at a low pressure of CO (6 to 8 bars). 相似文献
44.
A naturally occurring Cameroonian smectite clay has been grafted with trimethylpropylammonium groups and the resulting organoclay deposited as thin film onto a glassy carbon electrode (GCE) surface. It was then exploited as a suitable matrix for the accumulation and the electrochemical detection of ascorbic acid (AA) and uric acid (UA). Cyclic voltammetry revealed an increase in oxidation peak responses along with a negative shift of the corresponding anodic peak potential for both AA and UA species when using the organoclay coated GCE in comparison with the bare electrode. The electroanalytical response was improved by coating the electrode surface with a first layer of sublimed ferrocene (FC(s)), and then overcoating with the organoclay film to avoid the mediator leaching. The resulting bilayer film exhibited good characteristics such as extended linear range and high sensitivities for AA and UA, in cyclic voltammetry and amperometry. Interestingly, the redox mediator FC(s) was likely to lower overpotentials for AA oxidation (but not for UA), making possible the selective detection of these species in a mixture. The developed method could be used for the determination of AA in a pharmaceutical preparation and for UA in urine. 相似文献
45.
Dr. Govind V. Kaigala Robert D. Lovchik Dr. Emmanuel Delamarche 《Angewandte Chemie (International ed. in English)》2012,51(45):11224-11240
Local interactions between (bio)chemicals and biological interfaces play an important role in fields ranging from surface patterning to cell toxicology. These interactions can be studied using microfluidic systems that operate in the “open space”, that is, without the need for the sealed channels and chambers commonly used in microfluidics. This emerging class of techniques localizes chemical reactions on biological interfaces or specimens without imposing significant “constraints” on samples, such as encapsulation, pre‐processing steps, or the need for scaffolds. They therefore provide new opportunities for handling, analyzing, and interacting with biological samples. The motivation for performing localized chemistry is discussed, as are the requirements imposed on localization techniques. Three classes of microfluidic systems operating in the open space, based on microelectrochemistry, multiphase transport, and hydrodynamic flow confinement of liquids are presented. 相似文献
46.
Emmanuel F. Olasehinde Ajibola V. Adegunloye Matthew A. Adebayo Aladesanmi A. Oshodi 《Analytical letters》2018,51(17):2708-2730
The efficacy of onion skins, both unmodified and chemically modified with thioglycolic acid, was investigated as alternative low-cost adsorbents for the sequestration of aqueous lead(II) ions from aqueous solution. The adsorbents were characterised using Fourier transform infrared spectroscopy and scanning electron microscopy – energy dispersive X-ray spectroscopy. Adsorption experiments were performed using batch sorption processes. The effects of contact time, pH, initial Pb(II) concentration, adsorbent dose, and temperature were investigated. Optimum sorption conditions were found at pH 4 and a 150?min equilibrium time for the modified onion skin and unmodified onion skin. The Langmuir, Freundlich, Dubinin-Radushkevich and Temkin models were used to characterize the equilibrium experimental results. The equilibrium process was best described by the Freundlich isotherm. The maximum adsorption capacities of 4.878 and 6.173?mg/g were obtained for modified and unmodified adsorbents, respectively, using the Langmuir model. Kinetic studies indicated that the sorption of Pb(II) ions followed a pseudo-second-order model. Thermodynamic parameters such as standard enthalpy change (ΔH°), entropy change (ΔS°), and free energy change (ΔG°) were evaluated from the sorption experimental measurements. The results showed that the sorption process of Pb(II) ions on unmodified and modified onion skins was feasible and exothermic under the conditions used in this study. The sorption process followed the mechanism of physisorption. 相似文献
47.
Mauricio Carrillo-Tripp Leonardo Alvarez-Rivera Omar Israel Lara-Ramírez Francisco Javier Becerra-Toledo Adan Vega-Ramírez Emmanuel Quijas-Valades Eduardo González-Zavala Julio Cesar González-Vázquez Javier García-Vieyra Nelly Beatriz Santoyo-Rivera Sergio Victor Chapa-Vergara Amilcar Meneses-Viveros 《Journal of computer-aided molecular design》2018,32(8):869-876
Research on biology has seen significant advances with the use of molecular dynamics (MD) simulations. The MD methodology enables explanation and discovery of molecular mechanisms in a wide range of natural processes and biological systems. The need to readily share the ever-increasing amount of MD data has been hindered by the lack of specialized bioinformatic tools. The difficulty lies in the efficient management of the data, i.e., in sending and processing 3D information for its visualization. In this work, we present HTMoL, a plug-in-free, secure GPU-accelerated web application specifically designed to stream and visualize MD trajectory data on a web browser. Now, individual research labs can publish MD data on the Internet, or use HTMoL to profoundly improve scientific reports by including supplemental MD data in a journal publication. HTMoL can also be used as a visualization interface to access MD trajectories generated on a high-performance computer center directly. Furthermore, the HTMoL architecture can be leveraged with educational efforts to improve learning in the fields of biology, chemistry, and physics. 相似文献
48.
Back Cover: Single‐Nanoparticle Cell Barcoding by Tunable FRET from Lanthanides to Quantum Dots (Angew. Chem. Int. Ed. 41/2018) 下载免费PDF全文
49.
GuyEmmanuel Raoelison Christian Terreaux EmersonFerreira Queiroz Ferenc Zsila Miklos Simonyi Sandor Antus Adolphe Randriantsoa Kurt Hostettmann 《Helvetica chimica acta》2001,84(11):3470-3476
The stem bark CH2Cl2 extract of Ravensara crassifolia showed antifungal activity against the phytopathogenic fungus Cladosporium cucumerinum in a bioautographic TLC assay. Activity‐guided fractionation afforded two new α‐pyrones : (6S)‐5,6‐dihydro‐6‐[(2R)‐2‐hydroxy‐6‐phenylhexyl]‐2H‐pyran‐2‐one ( 1 ) and (6R)‐6‐[(4R,6R)‐4,6‐dihydroxy‐10‐phenyldec‐1‐enyl]‐5,6‐dihydro‐2H‐pyran‐2‐one ( 2 ). Their structures and absolute configurations were established by NMR spectroscopy, chemical methods, and CD spectroscopy. The antifungal activity against C. cucumerinum was determined for both compounds. 相似文献
50.
Emmanuel A. Adegoke Babajide I. Alo Oluwole B. Familoni 《Journal of heterocyclic chemistry》1987,24(1):107-110
Regiospecific synthesis of 4H-3,3a-dihydrothiazolo[4,3-b]quinazolines and 7-methyl-4H-3,3a-dihydrothiazolo[4,3-b]quinazolines IVa and IVb is described. The N-substituted thiazolidinecarboxylic acids Ia and Ib were converted to the corresponding acid chlorides, IIa and IIb but neither reacted with silver trifluoromethanesulphonate. The carboxylic acids Ic and Id were however, decarboxylated to the corresponding iminium ions using phosphorus oxychloride and these afforded the nitroamines IIIa and IIIb. Reductive cyclisation led to the quinazolines IVa and IVb. 相似文献