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21.
Castaldelli E Triboni ER Demets GJ 《Chemical communications (Cambridge, England)》2011,47(19):5581-5583
This naphthalene diimide derivative, DC18, forms highly conjugated semiconducting stacked assemblies over electrodes after electrochemical conditioning. These molecular materials are very efficient towards electrochemical photoreduction of oxygen under visible light. 相似文献
22.
A general quantitative treatment for salt effects by means of an empirical relationship between the observed rates k and the concentrations of added electrolyte is presented. The proposed equation has been successfully tested for a variety of processes in the literature. 相似文献
23.
Jorge Rezende 《Letters in Mathematical Physics》1996,38(2):117-127
In this Letter, a theorem on time-dependent linear Hamiltonian systems is recalled and its connection with the Schrödinger equation is discussed. The kernel of the evolution operator of such quantum systems is computed. Furthermore, the Lewis and Riesenfeld theory for systems with many degrees of freedom is generalized. 相似文献
24.
25.
The radiation induced linewidth of magnetostatic modes in spheres of Yttrium Iron Garnet has been measured in microwave experiments. The linewidths of the lowest order modes (n m 0) have a ω2n+1 frequency dependence which can be explained by multipole radiation. 相似文献
26.
S.M. Rezende Cid.B. de Araujo E. Montarroyos V. Jaccarino 《Solid State Communications》1980,35(8):627-630
A study of the local magnon mode in FeF2 crystals with Mn2+ impurities by inelastic Raman light scattering is presented. Though the interaction between the radiation and the Mn spins is negligible the scattering by the s0 local mode is very strong. The data of the frequency and the scattering intensity are analyzed in terms of a magnetization coupled mode approach. 相似文献
27.
B. N. Sismanoglu K. G. Grigorov R. A. Santos R. Caetano M. V.O. Rezende Y. D. Hoyer V. W. Ribas 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,60(3):479-487
Linear Stark splitting of the H\(_{\beta}\) Balmer line components and spatially resolved optical emission spectroscopy (OES) measurements were used to estimate the electric field gradient in the cathode sheath region (~70 μm long) of an atmospheric pressure direct current argonflow-stabilized microplasma jet. Also, plasma parameters in the negative glow region were investigated by both OES and electrical diagnostics. The microplasma jet was operated for current ranging from 10 to 110 mA. OH (A2 \({\rm\Sigma}^+\), v = 0 \(\to\) X 2 \({\rm\Pi}\), v’ = 0) rotational bands at 306.357 nm and also the Ar 603.213 nm line were used to determine the gas temperature, which ranges from 600 to 1000 K. Electron number density, ranging from4.1 × 1014 to 8.5 × 1014 cm-3, was determined through analysis of the H\(_{\beta}\) line.Electron excitation temperature was also measured from the ratio of two Mo lines (8500–18?000 K) and from Boltzmann-plot of Ar 4p–4s and 5p–4s transitions (11?000–13?500 K). 相似文献
28.
Kemilly M. P. Pinheiro Roger C. Moreira Kariolanda C. A. Rezende Mrcio Talhavini Lucio P. L. Logrado Jos A. F. Baio Marcos R. V. Lanza Wendell K. T. Coltro 《Electrophoresis》2019,40(3):462-468
This study describes the development of an analytical methodology based on the use of microchip electrophoresis (ME) devices integrated with capacitively coupled contactless conductivity detection (C4D) for the separation and detection of inorganic anions in post‐blast explosive residues. The best separation condition was achieved using a running buffer composed of 35 mmol/L lactic acid, 10 mmol/L histidine and 0.070 mmol/L cetyl(trimethyl ammonium) bromide. For C4D measurements, the highest sensitivity was obtained applying a 700 kHz sinusoidal wave with excitation voltage of 20 Vpp. The separation of Cl?, NO3?, NO2?, SO42?, ClO4? and ClO3? was performed within ca. 150 s with baseline resolution and efficiencies between 4.4 × 104 and 1.7 × 105 plates/m. The found limits of detection ranged between 2.5 and 9.5 μmol/L. Last, real samples of post‐blast explosive residues were analyzed on the ME‐C4D devices obtaining successfully the determination of Cl?, NO3? and SO42?. The achieved concentration values varied between 12.8–72.5 mg/L for Cl?, 1.7–293.1 mg/L for NO3? and 1.3–201.3 mg/L for SO42?. The data obtained using ME‐C4D devices were in good agreement with the concentrations found by ion chromatography. The approach reported herein has provided short analysis time, instrumental simplicity, good analytical performance and low cost. Furthermore, the ME‐C4D devices emerge as a powerful and portable analytical platform for on‐site analysis demonstrating to be a promising tool for the crime scene investigation. 相似文献
29.
Alves de Rezende C Lee LT Galembeck F 《Langmuir : the ACS journal of surfaces and colloids》2008,24(14):7346-7353
The interfacial behavior of silica nanoparticles in the presence of an amphiphilic polymer poly( N-isopropylacrylamide) (PNIPAM) and an anionic surfactant sodium dodecyl sulfate (SDS) is studied using neutron reflectivity. While the nanoparticles do not show any attraction to hydrophilic and hydrophobic surfaces in pure water, presence of the amphiphilic polymer induces significant adsorption of the nanoparticles at the hydrophobic surface. This interfacial behavior is activated due to interaction of the nanoparticles with PNIPAM, the amphiphilic nature of which leads to strong adsorption at a hydrophobic surface but only weak interaction with a hydrophilic surface. The presence of SDS competes with nanoparticle-PNIPAM interaction and in turn modulates the interfacial properties of the nanoparticles. These adsorption results are discussed in relation to nanoparticle organization templated by dewetting of charged polymer solutions on a solid substrate. Our previous studies showed that nanoparticle assembly can be induced to form complex morphologies produced by dewetting of the polymer solutions, such as a polygonal network and long-chain structures. This approach, however, works on a hydrophilic substrate but not on a hydrophobic substrate. These observations can be explained in part by particle-substrate interactions revealed in the present study. 相似文献
30.
MJ Briones R Bol D Sleep L Sampedro D Allen 《Rapid communications in mass spectrometry : RCM》1999,13(13):1300-1304
Changes in the specific diet of earthworms with time in relation to landuse changes and two different climates were studied by analysing (13)C and (15)N natural abundance in soils and animals. Soil samples from three depths (0-10, 10-20 and 20-30 cm) and earthworms were collected from two sites: Santiago (Northwest Spain) and North Wyke (Southwest England) both consisting of replicated long-term grasslands and recently converted to maize plots. Earthworms were hand-sorted in the field at the peak of the maize growth and after harvesting at both sites. In the Spanish plots, nine and eight earthworm species, all belonging to the three ecological categories (epigeic, anecic and endogeic), were found under maize and permanent pasture, whereas at the English site five and seven different species were, respectively, identified. At both sites (13)C isotopic values of the earthworm tissues reflected changes in diet from C(3) to C(4) with epigeic and epi/anecic worms in the maize plots showing one delta unit difference in relation to the ones found in the grassland plots. Anecic worms seemed to be less responsive to landuse changes. The higher (13)C values of the Spanish soils were also reflected in the earthworm tissues when compared with the English samples. (15)N values showed no clear relationship with the cropping treatments but were clearly related to the ecological grouping, with endogeic worms reaching the highest values whereas for the epigeic and epi/anecic species the lowest values were obtained. This finding was also previously recorded by other authors1 and suggests that, in the future, stable isotope techniques could also be a useful tool in taxonomic studies. Copyright 1999 John Wiley & Sons, Ltd. 相似文献