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241.
Background
Clinical spinal cord injury in domestic dogs provides a model population in which to test the efficacy of putative therapeutic interventions for human spinal cord injury. To achieve this potential a robust method of functional analysis is required so that statistical comparison of numerical data derived from treated and control animals can be achieved. 相似文献242.
João Cura D’Ars de Figueiredo Junior Vanessa de Freitas Cunha Lins 《Applied Surface Science》2007,253(17):7104-7107
The corrosion products of a TM 23 bronze-leaded alloy (Cu 72%, Pb 15%, Zn 8% and Sn 5%) were obtained in a salt spray cabinet after exposition during 120 h and 1000 h. The products obtained were studied using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. The major products of bronze-leaded corrosion were oxides and basic salts of Cu, CuCl2·3Cu(OH)2, and Pb, Pb(OH)Cl. The results can be attributed to a kinetic control of the corrosion reactions. 相似文献
243.
The standard electroweak interaction is here re‐assessed to accommodate two different situations in Particle Physics. The first one is a ‐model at the TeV‐scale physics. The second one tackles the recent discussion of a possible fifth force mediated by a 17‐MeV X‐boson associated with an electron‐positron emission in the transition of an excited 8‐Beryllium to its ground state. The anomaly‐free model that provides these two scenarios is based on an ‐symmetry. It yields a new massive neutral boson, an exotic massive neutral fermion, right‐neutrinos and an additional neutral Higgs particle, which stems from a supplementary Higgs field, introduced along with the usual Higgs doublet responsible for the electroweak breaking and the masses of and Z0. Yukawa interactions of the two scalars generate the masses of the Standard Model leptons, neutrinos and a new exotic fermion of the model. The vacuum expectation values of the Higgses fix up two independent energy scales. One of them is the well‐confirmed electroweak scale, 246 GeV, whereas the other one is set up by adopting an experimental estimate for the ‐mass. 相似文献
244.
Error growth in the numerical integration of periodic orbits by multistep methods, with application to reversible systems 总被引:4,自引:0,他引:4
We study the growth with time of (the coefficients of the asymptoticexpansion of) the error in the numerical integration with linearmultistep methods of periodic solutions of systems of ordinarydifferential equations. Particular attention is devoted to reversiblesystems. It turns out that symmetric linear multistep methodscannot be recommended in spite of the fact that they mimic thereversibility of the true flow. For reversible second-ordersystems, linear multistep methods without parasitic double rootsare useful. 相似文献
245.
A. Gevaerd E. Y. Watanabe K. Fernandes M. A. P. Papi C. E. Banks M. F. Bergamini L. H. Marcolino‐Junior 《Electroanalysis》2020,32(8):1689-1695
In this study, electrochemically reduced graphene oxide (ERGO) was used for the preparation of a screen‐printed modified electrode and applied for the voltammetric determination of fenamiphos (FNP) in tomato samples. Graphene oxide (GO) used for sensor construction was prepared according to an improved Hummers method and characterized by XRD, TEM, and FTIR, which confirmed the nanomaterial obtention. The ERGO formation was carried out from the electrodeposition by cyclic voltammetry, at 50 mV s?1 in the potential range of 0.0 to ?1.5 V, during 50 cycles. ERGO‐SPE was used in the evaluation of the voltammetric behavior of FNP. The ERGO‐SPE proposed presented excellent electrochemical performance towards FNP oxidation, promoting an enhance on the anodic peak current and a decrease of peak potential. Under optimized conditions, it was possible to construct an analytical curve, using square wave voltammetry, with a linear region of 0.25 to 25.0 μM, with calculated limits of detection and quantification of 0.067 and 0.22 μM. From this, it was possible to analyze FNP in fortified tomato samples at three concentration levels, which showed recoveries values varying between 82 and 102 %. The ERGO‐SPE device proved useful in determining FNP, where the effect of the electrodeposition of the GO promoted a significant increase in the employability of the printed electrode. 相似文献
246.
H.O. Rodrigues G.F.M. Pires Junior A.J.M. Sales P.M.O. Silva B.F.O. CostaP. Alcantara Jr S.G.C. MoreiraA.S.B. Sombra 《Physica B: Condensed Matter》2011,406(13):2532-2539
In this paper Mössbauer, Raman and dielectric spectroscopy studies of BiFeO3 (BFO) ceramic matrix with 3 or 10 wt% of Bi2O3 or PbO added, obtained through a new procedure based on the solid-state method, are presented. Mössbauer spectroscopy shows the presence of a single magnetically ordered phase with a hyperfine magnetic field of 50 T. Raman spectra of BFO over the frequency range of 100-900 cm−1 have been investigated, at room temperature, under the excitation of 632.8 nm wavelength in order to evaluate the effect of additives on the structure of the ceramic matrix. Detailed studies of the dielectric properties of BiFeO3 ceramic matrix like capacitance (C), dielectric permittivity (ε) and dielectric loss (tan δ), were investigated in a wide frequency range (1 Hz-1 MHz), and in a temperature range (303-373 K). The complex impedance spectroscopy (CIS) technique, showed that these properties are strongly dependent on frequency, temperature and on the added level of impurity. The temperature coefficient of capacitance (TCC) of the samples was also evaluated. The study of the imaginary impedance (−Z″) and imaginary electric modulus (M″) as functions of frequency and temperature leads to the measurement of the activation energy (Eac), which is directly linked to the relaxation process associated with the interfacial polarization effect in these samples. 相似文献
247.
Luzia Patricia Fernandes Carvalho Galvão Anne Gabriella Dias Santos Amanda Duarte Gondim Marcela Nascimento Barbosa Antonio Souza Araujo Luiz Di Souza Valter José Fernandes Junior 《Journal of Thermal Analysis and Calorimetry》2011,106(2):625-629
Biodiesel can contain unsaturated fatty acids, which are susceptible to oxidation, being able to change into polymerized compounds.
Oxidative stability is very important in the quality control of oils and biodiesel. In this study, biodiesel samples were
produced through the methyl route, using a homogeneous catalyst. The determination of methyl esters was performed by gas chromatography
in order to confirm the conversion of the carboxylic acids present in the raw material for the methyl esters. Also proved
the presence of methyl linoleate and methyl oleate to the major constituent of biodiesel. The thermal and oxidative stability
of sunflower and cotton oils and their biodiesel, using TG and P-DSC techniques were investigated. The use of P-DSC to measure
the oxidative induction time was very important. These measurements were used to evaluate the cotton and sunflower oils, and
their respective biodiesel. It was found that the thermal-oxidative stability of vegetable oils and their biodiesel were similar,
due to the fact that both presented chemical composition and percentages of fatty acids similar. 相似文献
248.
Sabrina Metairon Cibele B. Zamboni Miriam F. Suzuki Carlos R. Bueno Junior Osvaldo A. Sant’Anna 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(1):579-584
Radioactivity measurement of short-lived nuclides is the basis of decay data measurement, which requires rapid separation and purification of the interested nuclides from complicated fission products. A rapid separation system based on SISAK and extraction chromatography technique was established to isolate 95Y, which half-life is 10.3 min. With the best conditions studied in this paper, 95Y was separated successfully from complicated fission products under the mini-reactor in the China Institute of Atomic Energy. Decontamination factors to other nuclides except 94Y are higher than 2 × 103. 相似文献
249.
Alex Neves Junior Mariana Santos Lemos Romildo Dias Toledo Filho Eduardo de Moraes Rego Fairbairn Jo Dweck 《Journal of Thermal Analysis and Calorimetry》2013,113(2):659-665
This work complements a quantitative thermogravimetric study of the first 24 h of hydration of a high initial strength and sulphate resistant Portland cement (HS SR PC) using non-conventional differential thermal analysis (NCDTA) and Vicat needle method. Different water/cement (W/C) ratios from 0.35 to 0.85 were used to evaluate the most indicated operating conditions to maximize calcium hydroxide production for further use in CO2 capture. Thermogravimetric analysis data performed at 4 and 24 h of hydration were also compared to the NCDTA and Vicat data for each kind of paste, to analyze the influence of the W/C ratio on the simultaneous hydration and setting process. The increase of the W/C ratio increases the induction time retards the solidification and setting processes but increases the hydration degree as the W/C ratio is increased from 0.45. At 24 h, products prepared with 0.35 W/C ratio present a little higher hydration degree than those prepared with W/C = 0.45, because of the highest level of temperature in the reacting mixture in the former case, during the first 8 h. There is a practical limit of W/C = 0.66 to prepare the pastes, due to a limit of the miscibility between HS SR PC and water, above which, the excess of water forms a separated phase that does not interfere in the hydration process. 相似文献
250.
Fabrício RS Pereira Andréa Alessio Maurício S Sercheli Tatiane Pedro Elizabeth Bilevicius Jane M Rondina Helka FB Ozelo Gabriela Castellano Roberto JM Covolan Benito P Damasceno Fernando Cendes 《BMC neuroscience》2010,11(1):1-13