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1.
Jos A. Gmez-Pedrero Juan A. Quiroga M. Jos Terrn-Lpez Daniel Crespo 《Optics and Lasers in Engineering》2006,44(12):1297-1310
In this paper we present the application of a direct demodulation method for the measurement of surface topography by means of Shadow-Moiré. In our set-up, we use three LEDs (with green, red and blue peak wavelengths) to illuminate the grating. Due to the different position of these light sources, a polychromatic Shadow-Moiré fringe pattern is produced, which can be described as the superposition of three monochromatic (red, green and blue) fringe patterns. Taking the image of this polychromatic fringe pattern with a RGB CCD camera, we get a monochromatic fringe pattern stored at each RGB channel of the CCD. The direct demodulation algorithm employed uses these fringe patterns to calculate the wrapped phase map. After unwrapping the phase map using a standard multi-grid technique, we implemented an automatic procedure to detect the area of interest of the phase map by removing low modulation zones and to calculate the absolute value of the phase. In this way it is possible to determine the topography of a surface with a single RGB snapshot maintaining a simple experimental set-up, which is an important feature, especially for the study of dynamic phenomena such as deformations. We present the experimental results obtained after measuring different objects with both smooth and rough surface textures. 相似文献
2.
Chemical, structural, and thermal properties of Zn(II)-Cr(III) layered double hydroxides intercalated with sulfated and sulfonated surfactants 总被引:1,自引:0,他引:1
Crepaldi EL Pavan PC Tronto J Valim JB 《Journal of colloid and interface science》2002,248(2):429-442
Zn(II)-Cr(III)-LDHs (layered double hydroxides) containing sulfated or sulfonated surfactants as the interlamellar anion were synthesized by the coprecipitation method. The syntheses were conducted under various different experimental conditions, such as the Zn : Cr ratio, pH, and aging time. In each of the prepared materials, unlike previously reported data, the interlayer anion arrangement did not change, being consistent with a perpendicular monolayer. The thermal decomposition process of the prepared materials was studied by a set of analysis methods, such as TG/DTA, TG/MS, PXRD, and FT-IR. From the results obtained it was possible to conclude that, in an air atmosphere, the anions decomposed by a partial combustion, leading to the formation of sulfide. The results also showed that sulfonated surfactants containing LDHs are much more stable than those containing sulfated surfactants. A mechanism was proposed for the thermal decomposition of such LDHs based on the experimental results. 相似文献
3.
Braulio Insuasty Fernando Fernandez Jairo Quiroga Rodolfo Moreno Roberto Martinez Enrique Angeles Ruban Gavito Regina H. S. De Almeida 《Journal of heterocyclic chemistry》1998,35(4):977-981
The reaction of 1,2-diaminobenzenes with substituted 1,2-dibenzoyl-1,2-dibromoethanes constitutes a convenient synthetic route to the hitherto 2-(p-R-benzoylmethylene)-3-(p-R-phenyl)-1H-quinoxalines. Structures of all products were elucidated by ir, 1H and 13C-nmr, mass spectra data. X-Ray crystallography data confirm assigned structures. 相似文献
4.
J. Quiroga J. Portilla B. Insuasty R. Abonía M. Nogueras M. Sortino S. Zacchino 《Journal of heterocyclic chemistry》2005,42(1):61-66
The synthesis of a series of bis‐pyrazolo[3,4‐b:4′,3′‐e]pyridines ( 3 ) in the reaction of 5‐amino‐3‐methyl‐1‐phenylpyrazole ( 1 ) with aldehydes ( 2 ) under microwave irradiation and solvent‐free conditions is described. The structure elucidation of the products is based on detailed nmr analysis of experiments such as 1H‐COSY, NOESY, DEPT, HSQC and HMBC. These compounds showed moderate antifungal in vitro activity against dermatophytes. 相似文献
5.
Luis A.?León Rafael?Notario Jairo?QuijanoEmail author Ederley?Vélez Claudia?Sánchez J. Camilo?Quijano Nouria?Al-Awadi 《Theoretical chemistry accounts》2003,110(6):387-394
Theoretical studies on the thermolysis in the gas phase of 4-arylideneimino-1,2,4-triazol-3(2H)-ones and 4-arylideneimino-1,2,4-triazol-3(2H)-thiones were carried out using density functional theory methods, at the B3LYP/6-31G(d) and B3LYP/6-311+G(2d,p) levels of theory. The proposed reaction mechanism occurs in one step, leading to the formation of 3-hydroxy-(2H)-1,2,4-triazole or 3-mercapto-(2H)-1,2,4-triazole and a 4-substituted benzonitrile, via a six-membered cyclic transition state. The progress of the reactions was followed by means of the Wiberg bond indices. The results indicate that the transition states have character intermediate between reactants and products, and the calculated synchronicities show that the reactions are slightly asynchronous, in the case of triazolones, and show a higher asynchronicity in the case of triazolthiones. The bond-breaking processes are slightly more advanced than the bond-forming ones, indicating a small bond deficiency in the transition states. Kinetic and activation parameters for the reactions studied have been calculated and compared with available experimental data.From the Proceedings of the 28th Congreso deQuímicos Teóricos de Expresión Latina (QUITEL 2002) 相似文献
6.
H. Kurcbart S. Quiroga R. A. Caro R. Radicella 《Journal of Radioanalytical and Nuclear Chemistry》1972,12(1):547-552
A photocolorimetric microtechnique is described, by which it is possible to determine the real amount of iodine in carrier-free
solutions of131INa. The method is conceptually based on the well-known effect of iodine, by which the rate of reduction of ceric sulfate
by arsenious acid in sulfuric acid solutions is proportional to the iodide concentration. The tittration and the preparation
of its corresponding calibration graph require approximately 90 min; thus, it seems possible to use this technique as a routine
analysis. Under the stated conditions of temperature and reaction time, it is possible to determine samples of iodine with
concentrations ranging between 20 and 160 ng/ml. The standard error between different determinations is less than ±5%. The
application of the method in production control and utilization of carrier-free131I solutions, free from reducing agent, are discussed. 相似文献
7.
Jossang A Cavé A Saez J Bartoli MH Cavé A Jossang P 《The Journal of organic chemistry》1996,61(9):3023-3030
Monterine 1 as well as granjine 3, 1R,1'S configured biphenylic bisbenzylisoquinoline alkaloids, generate two highly populated conformers. The interconversion of two forms was detected by saturation tranfer in (1)H NMR NOEs experiments. Tridimensional structure of the conformers was determined on the basis of (1)H NMR analysis of anisotropic shielding protons, by NOEs measurements and vicinal proton coupling constants of CH1-CH(2)alpha and CH1'-CH(2)alpha'. The structures established from NMR data were further refined to observe the mobility of 3D conformations by molecular dynamics simulation in vacuo. The highly populated conformers, monterine 1a and 1b, as well as granjine 3a and 3b, are interconvertible by rotation about the C1'-Calpha', Calpha'-C9', and C11'-C11 bonds and inversion of the benzyl D ring by reference to CH(2)alpha'. The slow exchange system was investigated by dynamic NMR spectroscopy: DeltaG()(c) 77.9 KJ/mol and k(c) 200 s(-)(1) for monterine 1; DeltaG()(c) 77.7 KJ/mol and k(c) 211 s(-)(1) for granjine 3. Natural and synthetic biphenylic bisbenzylisoquinolines displayed, in vitro, cytotoxic activities against human prostate and breast cancer cell lines. 相似文献
8.
Braulio Insuasty Jairo Quiroga Juan Carlos Argoti Samuel Gmez Roberto Martínez Enrique Angeles Rubn Gabio Manuel Nogueras Adolfo Snchez 《Journal of heterocyclic chemistry》1998,35(6):1397-1399
The reaction of 1-aryl-3-(dimethylamino)-1-propanones 1 with one equivalent of 4,5-diamino-1H-pyrimidin-6-ones 2 , in acidic medium, leads to the formation of 4-aryl-2,3,6,7-tetrahydro-1H-pyrimido[4,5-b]-[1,4]diazepin-6-ones 3 . The structure elucidation of the products is based on detail nmr analysis of experiments such as 13C, 1H and DEPT including selective 13C{1H} decoupling experiments. 相似文献
9.
Elena E. Stashenko William Torres Jairo Ren Martinez Morales 《Journal of separation science》1995,18(2):101-104
Volatile secondary metabolites from Colombian ylang-ylang flowers were obtained by combined steam distillation - solvent extraction. The samples were analyzed by high resolution gas chromatography with flame ionization, nitrogen/phosphorus, or mass spectrometric detection. The chemical composition of the oils extracted from flowers at different stages of development differed both qualitatively and quantitatively. The generation of total volatile metabolites, light oxygenated compounds in particular, increased markedly during flower maturation. In this work the quality of the ylang-ylang essential oils was studied as a function of flower maturity. 相似文献
10.
Jos Antonio Andrades Manuel Lojo-Lpez Agata Egea-Corbacho Jos María Quiroga 《Molecules (Basel, Switzerland)》2022,27(14)
Different advanced oxidation processes (AOPs) (ultraviolet radiation, hydrogen peroxide photolysis and photo-Fenton) were applied to test the degradation of terbuthylazine in three types of water: (a) ultrapure water, (b) surface water from the Gaditana area (Los Hurones reservoir, Cádiz, Spain) and (c) groundwater from the Tempul spring in Jerez de la Frontera (Cádiz, Spain). The experiments were carried out on a laboratory scale, using two different types of reactors, batch and semi-continuous. In batch reactors, the most efficient process for the experiments carried out with both ultrapure water and underground groundwater was ultraviolet radiation, whereas for surface water from the Gaditana area, the process that obtained the best results was the photolysis of hydrogen peroxide with 2.5 mg L−1 of H2O2. In semi-continuous reactors, the most efficient process was the photolysis of hydrogen peroxide with 2.5 mg L−1 of H2O2 for all the matrices studied. In both types of reactors, terbuthylazine degradation percentages higher than 90% were achieved; the main difference was in the reaction time, which varied from minutes in the batch reactor to seconds in the semi-continuous reactor. In all the applied AOPs, N-terbutyl-6-hydroxy-N′ethyl-1,3,5-triazine-2,4-diamine (TBA-212) was generated as a reaction intermediate. 相似文献