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71.
Ana M. Costero Ursula Llaosa Salvador Gil Margarita Parra Manuel Colera 《Tetrahedron: Asymmetry》2009,20(13):1468-1471
Two new cyclohexane-based thiourea chiral ligands have been synthesized in their enantiomerically pure forms. Both the ability of these ligands in the complexation of chiral dicarboxylates and their sensing properties have been studied. The influence of the stoichiometry of the formed complexes on the fluorescent properties of the systems has been established. The effect of additional substitution in the cyclohexyl moiety was considered by comparing the properties of the newly prepared ligands with those of similar compounds previously described. 相似文献
72.
73.
Combined parametric optimization of P3HT: PC70BM films for efficient bulk-heterojunction solar cells
Siddiqui Hafsa Parra Mohammad Ramzan Pandey Padmini Qureshi M. S. Haque Fozia Zia 《Journal of Solid State Electrochemistry》2019,23(12):3267-3274
Journal of Solid State Electrochemistry - In this report, the effects of photoactive blend compositions, film thicknesses, and annealing conditions on the P3HT:PC70BM solar cells performance and... 相似文献
74.
Two homologous series of esters derived from Schiff's bases containing the 1,3,4-thiadiazole unit (series 3 and 5) were synthesized and their liquid crystalline properties investigated by optical microscopy and differential scanning calorimetry. Depending on the position occupied by the carbonyl group, the smectic A phase was observed in series 3 and nematic phase in series 5. 相似文献
75.
76.
C. Barba M. Martí A. Roddick-Lanzilotta A. Manich J. Carilla J. L. Parra L. Coderch 《Journal of Thermal Analysis and Calorimetry》2010,102(1):43-48
Most beauty care products and treatments primarily affect the cuticle layers of hair fibers. The resulting damage has an adverse
effect on hair water absorption. Water changes a wide variety of properties of human hair and is therefore of fundamental
interest. Wool proteins are mild, natural, biodegradable, and sustainably produced with multiple functionalities and potential
for use in the personal care and detergent market. In this study, the effect on hair water sorption of two types of keratin
samples obtained from wool is investigated. Modifications of hair water sorption due to a bleaching treatment have been demonstrated,
with lower values of water sorption capacity and an increase of the fibers permeability. Applications of keratin peptides
and proteins to bleached hair improved the water sorption properties of the fibers and reduced their permeability. 相似文献
77.
Abdelaziz Kacha My Hassan Hbid Rafael Bravo de la Parra 《Nonlinear Analysis: Real World Applications》2009,10(3):1662-1678
In this paper, we propose a mathematical model to study a bacteria–fish system, based upon the interactions between Clostridium botulinum and tilapia, Oerochromis mossambicus. The fish population is divided into susceptible and infected, and the infected fish population is considered structured by the level of infection. The model is thus a system with the infected fish equation being an evolution equation, while those corresponding to the susceptible fish and bacteria in water are ordinary differential equations. The model is firstly transformed into a system with distributed delay for susceptible fish and bacteria and, further, under some assumptions, into a system with discrete delay. The study of this system gives us some results concerning the existence, uniqueness, positivity and boundedness of solutions; we also discuss the existence and stability of its equilibrium points, including conditions for the appearance of Hopf bifurcation. The theoretical results are illustrated by some numerical simulations. 相似文献
78.
Zheng Z Stroumpoulis D Parra A Petzold L Tirrell M 《The Journal of chemical physics》2006,124(6):64904
A general lattice Monte Carlo model is used for simulating the formation of supported lipid bilayers (SLBs) from vesicle solutions. The model, based on a previously published paper, consists of adsorption, decomposition, and lateral diffusion steps, and is derived from fundamental physical interactions and mass transport principles. The Monte Carlo simulation results are fit to experimental data at different vesicle bulk concentrations. A sensitivity analysis reveals that the process strongly depends on the bulk concentration C(0), adsorption rate constant K, and all vesicle radii parameters. A measure of "quality of coverage" is proposed. By this measure, the quality of the formed bilayers is found to increase with vesicle bulk concentration. 相似文献
79.
Ana M. Costero Prof. Dr. Margarita Parra Dr. Salvador Gil Dr. Raúl Gotor Pedro M. E. Mancini Prof. Dr. Ramón Martínez‐Máñez Prof. Dr. Félix Sancenón Dr. Santiago Royo 《化学:亚洲杂志》2010,5(7):1573-1585
A family of azo and stilbene derivatives ( 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ) are synthesized, and their chromo‐fluorogenic behavior in the presence of nerve‐agent simulants, diethylchlorophosphate (DCP), diisopropylfluorophosphate (DFP), and diethylcyanophosphate (DCNP) in acetonitrile and mixed solution of water/acetonitrile (3:1 v/v) buffered at pH 5.6 with MES, is investigated. The prepared compounds contain 2‐(2‐N,N‐dimethylaminophenyl)ethanol or 2‐[(2‐N,N‐dimethylamino)phenoxy]ethanol reactive groups, which are part of the conjugated π‐system of the dyes and are able to give acylation reactions with phosphonate substrates followed by a rapid intramolecular N‐alkylation. The nerve‐agent mimic‐triggered cyclization reaction transforms a dimethylamino group into a quaternary ammonium, inducing a change of the electronic properties of the delocalized systems that results in a hypsochromic shift of the absorption band of the dyes. Similar reactivity studies are also carried out with other “non‐toxic” organophosphorus compounds, but no changes in the UV/Vis spectra were observed. The emission behaviour of the reagents in acetonitrile and water–acetonitrile 3:1 v/v mixtures is also studied in the presence of nerve‐agent simulants and other organophosphorous derivatives. The reactivity between 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 and DCP, DCNP, or DFP in buffered water–acetonitrile 3:1 v/v solutions under pseudo first‐order kinetic conditions, using an excess of the corresponding simulant, are studied in order to determine the rate constants (k) and the half‐life times (t1/2=ln2/k) for the reaction. The detection limits in water/acetonitrile 3:1 v/v are also determined for 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 and DCP, DCNP, and DFP. Finally, the chromogenic detection of nerve agent simulants both in solution and in gas phase are tested using silica gel containing adsorbed compounds 1 , 2 , 3 , 4 , or 5 with fine results. 相似文献
80.
Adriana N. Geraldes Heloísa A. Zen Geise Ribeiro Henrique P. Ferreira Camila P. Souza Duclerc F. Parra Elisabete I. Santiago Ademar B. Lugão 《Radiation Physics and Chemistry》2010,79(3):246-249
Grafting of styrene followed by sulfonation onto poly(ethylene-alt-tetrafluoroethylene) (ETFE) was studied for synthesis of ion exchange membranes. Radiation-induced grafting of styrene onto ETFE films was investigated after simultaneous irradiation (in post-irradiation condition) using a 60Co source. The ETFE films were irradiated at 20 kGy dose at room temperature and chemical changes were monitored after contact with styrene for grafting. The post-irradiation time was established at 14 days when the films were remained in styrene/toluene 1:1 v/v. After this period the grafting degree was evaluated in the samples. The grafted films were sulfonated using chlorosulfonic acid and 1, 2-dichloroethane 20:80 (v/v) at room temperature for 5 h. The membranes were analyzed by infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), thermogravimetric measurements (TG) and degree of grafting (DOG). The ion exchange capacity (IEC) of membranes was determined by acid–base titration and the values for ETFE membranes were achieved higher than Nafion® films. Preliminary single cell performance was made using pure H2 and O2 as reactants at a cell temperature of 80 °C and atmospheric gas pressure. The fuel cell performance of ETFE films was satisfactory when compared to state-of-art Nafion® membranes. 相似文献