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排序方式: 共有2921条查询结果,搜索用时 469 毫秒
91.
《Arabian Journal of Chemistry》2020,13(2):4082-4091
In present study, an investigation was carried out to develop and validate an analytical method for the selective extraction and determination of griseofulvin (GSF) from plasma samples. For this purpose, a rational approach was made to synthesize and characterize the surface molecularly imprinted polymers (SMIPs). The SMIPs were utilized as solid phase extraction (SPE) sorbents. The SMIPs were prepared by using GSF as template molecule on the surface of modified silica particles through a non-covalent technique. The particles demonstrated high adsorption capacity (119.1 µg/mL), fast adsorption equilibrium time (30 min) and good recognition selectivity for the template drug. The scanning electron microscopy and infrared spectroscopy were used to explain the structural and morphological characteristics of the SMIPs and surface non-imprinted polymers. The SPE method was combined with HPLC for plasma analysis. The method validation results demonstrated that the established method possessed good linearity for GSF ranging from 0.1 to 50 µg/mL (R2 = 0.997). The limit of detection for this method was 0.02 µg/mL for rat plasma samples. The recoveries of GSF from spiked plasma samples were (90.7–97.7%) and relative standard deviations were (0.9–4.5%). Moreover, the SMIPs as selective SPE sorbent can be reused more than 8 times which is a clear advantage over commercial SPE sorbents. Finally, the usefulness of the proposed strategy was assessed by extraction and detection of GSF in real rat plasma samples. 相似文献
92.
Stephanie Hansen G.S.J. Armstrong S. Bastiani-Ceccotti C. Bowen H.-K. Chung J.P. Colgan F. de Dortan C.J. Fontes F. Gilleron J.-R. Marquès R. Piron O. Peyrusse M. Poirier Yu. Ralchenko A. Sasaki E. Stambulchik F. Thais 《High Energy Density Physics》2013,9(3):523-527
Collisional-radiative atomic models are widely used to help diagnose experimental plasma conditions through fitting and interpreting measured spectra. Here we present the results of a code comparison in which a variety of models determined plasma temperatures and densities by finding the best fit to an experimental L-shell Kr spectrum from a well characterized, but not benchmarked, laser plasma. While variations in diagnostic strategies and qualities of fit were significant, the results generally confirmed the typically quoted uncertainties for such diagnostics of ±20% in electron temperature and factors of about two in density. The comparison also highlighted some model features important for spectroscopic diagnostics: fine structure was required to match line positions and relative intensities within each charge state and for density diagnostics based on emission from metastable states; an extensive configuration set was required to fit the wings of satellite features and to reliably diagnose the temperature through the inferred charge state distribution; and the inclusion of self-consistent opacity effects was an important factor in the quality of the fit. 相似文献
93.
Michael S. Gruhne Dr. Maximilian H. H. Wurzenberger Marcus Lommel Dr. Jörg Stierstorfer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(35):9112-9123
Dinitraminic acid (HN(NO2)2, HDN) was prepared by ion exchange chromatography and acid-base reaction with basic copper(II) carbonate allowed the in situ preparation of copper(II) dinitramide, which was reacted with twelve nitrogen-rich ligands, for example, 4-amino-1,2,4-triazole, 1-methyl-5H-tetrazole, di(5H-tetrazolyl)-methane/-ethane/-propane/-butane. Nine of the complexes were investigated by low-temperature X-ray diffraction. In addition, all compounds were investigated by infrared spectroscopy (IR), differential thermal analysis (DTA), elemental analysis (EA) and thermogravimetric analysis (TGA) for selected compounds. Furthermore, investigations of the materials were carried out regarding their sensitivity toward impact (IS), friction (FS), ball drop impact (BDIS) and electrostatic discharge (ESD). In addition, hot plate and hot needle tests were performed. Complex [Cu(AMT)4(H2O)](DN)2, based on 1-amino-5-methyltetrazole (AMT), is most outstanding for its detonative behavior and thus also capable of initiating PETN in classical initiation experiments. Laser ignition experiments at a wavelength of 915 nm were performed for all substances and solid-state UV-Vis spectra were recorded to apprehend the ignition mechanism. 相似文献
94.
The goal of the present experimental study is to investigate the ability of surface DBD plasma actuators to delay flow separation along the suction side of a NACA0015 airfoil. Three single surface DBD actuators that can operate separately are mounted on the suction side of the profile, at 18%, 27% and 37% of the chord length. The boundary layer is transitioned by a tripper to be sure that the flow control is not due to the laminar-to-turbulent transition. The angle of attack is equal to 11.5° and the free-stream velocity to U0 = 40 m/s, resulting in a chord-based Reynolds number of Rec = 1.33 × 106. The flow is studied with a high-resolution PIV system. In such conditions, the baseline flow separation occurs at 50% of chord. Then, the different single DBD have been switched on separately, in order to investigate the actuator location effect. One highlights that the DBD located at xc/c = 18% is more effective than the two others ones, with a separation delay up to 64% of chord. When the three DBDs operate simultaneously, the separation point moves progressively toward the trailing edge when the high voltage is increased, up to 76% of chord at 20 kV. Finally, the effect of the actuation frequency on the control authority has been investigated, by varying the value of the operating frequency and by burst-modulation. For frequencies equal to 50 Hz and 500 Hz (reduced frequency F+ = 0.31 and 3.1), the separation has been delayed at 76 and 80% of chord, respectively. 相似文献
95.
《High Energy Density Physics》2013,9(3):435-438
Absolute Kα line spectroscopy is proposed for studying laser–plasma interactions taking place in the Au cone-guided fast ignition targets. X-ray spectra ranging from 20 to 100 keV were quantitatively measured with a Laue spectrometer composed of a cylindrically curved crystal and a filter-absorption method for Bremsstrahlung continuum emission. The absolute sensitivities of the Laue spectrometer systems were calibrated using pre-characterized laser-produced X-ray sources and radioisotopes. The integrated reflectivity for the crystal is in good agreement with predictions by an X-ray diffraction code. The energy transfer efficiency from incident laser beams to hot electrons, as the energy transfer mechanism, is derived from this work. The absolute yield of Au and Ta Kα lines were measured in the fast ignition experimental campaign performed at Institute of Laser Engineering, Osaka University. Applying the hot electron spectrum information from electron spectrometer and scaling laws, the energy transfer efficiency from the incident LFEX, a kJ-class PW laser, to hot electrons was derived for the first time. 相似文献
96.
97.
The stabilization of partially-premixed jet flames in the presence of high potential electric fields
Numerous research efforts have focused on flame stabilization and emissions. Based on initial experiments, specific mechanisms resulting from DC electric fields were chosen to be investigated, namely the chemical, thermal, and ionization mechanisms. Numerical simulations were performed on premixed propane-ozone-air flames to characterize ozone effects on flame speed resulting from the formation of ozone in high potential electric fields. These results were compared against partially premixed flame experiments to observe the dominant influences within leading edge stabilization within high potential electric fields. It was found that the electromagnetic or ionization influences, serve as the dominant effect on the combustion zone. 相似文献
98.
Selenium has been identified as an essential dietary trace e1ementQ)which is a component of glutathione peroxidase (GSH-Px)(2)and a cytochrome C-like protein(3), The enzyme,the four subunits of which each contain one atom of selenium in the form of selenocysteine, the selenium containing active centre being amenable to chemical modification, catalyses the reduction of H,O,and organic hydroperoxides to water.In this way GSH-Px plays an important role in the protection of the cell from oxidative stresses such as the superoxide anion,organic hydroperoxides and H2O2 相似文献
99.
激光除漆是一种高效、清洁的新型清洗技术,对激光除漆物理过程和机理的研究是该技术发展的关键。基于LIBS技术,测量得到油漆去除过程中等离子体的发光光谱,计算出油漆样品去除前后等离子体的电子密度和温度,研究了油漆中特征元素对应的光谱特征峰强度随时间的变化情况。结果表明,随着激光作用脉冲数量的增加,油漆去除深度逐渐增加,等离子体电子密度和温度在将漆去除干净的最后几个脉冲作用时呈下降趋势。油漆中Ti元素的所对应的特征峰信号持续时间为2个μs,油漆去除前后信号强度呈现跳跃减少,该现象可用于快速、准确、实时的判断油漆去除情况。 相似文献
100.
《Current Applied Physics》2014,14(3):287-293
Lumped parameter models for describing dynamics of the plasma channel in a parallel-plate plasma gun are compared with the experimental results obtained from two plasma guns with different rail geometries. Comparison between the experiments and the numerical calculations reveals that the lumped parameter models can be utilized to describe the dynamic motion of the plasma channel quite well. Parametric study shows that minimizing the line inductance and increasing the charging voltage on a capacitor as well as minimizing the gas injection time for reducing the mass of the plasma channel are the key factors to increase the flow velocity of the plasma jet ejected from the plasma gun. 相似文献