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61.
Hari M. Srivastava Hatira Günerhan Behzad Ghanbari 《Mathematical Methods in the Applied Sciences》2019,42(18):7210-7221
The main aim of this article is to present some new exact solutions of the resonant nonlinear Schrödinger equation. These solutions are derived by using the generated exponential rational function method (GERFM). The kink‐type, bright, dark, and singular soliton solutions are reported, and several numerical simulations are also included. The calculations are carried out by Maple software. All of the solutions that are derived in this paper are believed to be new and have presumably not been reported in earlier publications. 相似文献
62.
1,3,5-Trisubstituted pyrazolines are rapidly and conveniently oxidized to their corresponding pyrazoles by 1,3-dichloro-5,5- dimethylhydantoin(DCH) in solution and solvent-free conditions under microwave irradiation.The presence of silica gel as a supporting agent is shown to be effective in reducing the reaction times and increasing the yields. 相似文献
63.
Maryam Rajabi Sudabeh Haji-Esfandiari Behruz Barfi Hanieh Ghanbari 《Analytical and bioanalytical chemistry》2014,406(18):4501-4512
In this study, the performances of four ionic-liquid-based microextraction methods, ionic-liquid-based dispersive liquid–liquid microextraction (IL-DLLME), ionic-liquid-based ultrasound-assisted emulsification microextraction (IL-USA-ME), temperature-controlled ionic-liquid dispersive liquid-phase microextraction (TC-IL-DLME), and ultrasound-assisted temperature-controlled ionic-liquid dispersive liquid-phase microextraction (USA-TC-IL-DLME), were investigated for extraction of three bioactive compounds (anethole, estragole, and anisaldehyde) from different plant extracts and human urine. Anethole and estragole were chosen because they can alter cellular processes positively or negatively, and an efficient method is needed for their extraction and sensitive determination in the samples mentioned. Because there is no previous report on the separation of anethole and estragole (structural isomers), first, simultaneous gradient elution and flow programming were used. The microextraction methods were then applied and compared for analysis of these compounds in plant extracts and human urine by use of high-performance liquid chromatography (HPLC). The effect of conditions on extraction efficiency was studied and under the optimum conditions, the best enrichment factors (58–64), limits of detection (14–18 ng mL?1), limits of quantification (47–60 ng mL?1), and recovery (94.4–101.7 %) were obtained by use of USA-TC-IL-DLME. The optimized conditions were used to determine anethole, estragole, and para-anisaldehyde in fennel, anise, and tarragon extracts and in human urine. 相似文献
64.
A. H. Mohagheghi F. Ghanbari S. B. Ebara M. E. Enghauser S. N. Bakhtiar 《Journal of Radioanalytical and Nuclear Chemistry》1998,234(1-2):261-266
The traditional method for determination, of alpha-emitting isotopes on air filters has been to process the samples by radiochemical
methods. However, this method is too slow for incidents involving radioactive materials where the determination of personnel
dose is urgent. A method is developed to directly analyze the air filters taken from personal and area air monitors. The site
knowledge is used in combination with alpha-spectral information to identify isotopes. A mathematical function is developed
to estimate the activity for each isotope. The strengths and weaknesses of the method are discussed. 相似文献
65.
66.
It is proposed that in a compact urban region fixed WiMAX (IEEE 802.16d) burst profiles can be adaptively selected according to the picture type of packets from an arriving encoded video stream. Because additional protection of anchor picture packets reduces the data rate, an algorithm dynamically selects less favourable burst profiles for less important packets. Under the stringent Stanford University Interim channel model, this simple scheme achieves as much as 10 dB gain in video quality at the receiver. 相似文献
67.
It is shown how the signal-to-noise (SNR) scaleable coder can benefit from optimizing quantified discrete cosine transform (DCT) coefficients, in a rate-distortion context, in order to reduce bit-rate overheads. The technique is based on adjusting the quantized coefficients rather than dropping them, since the former gives finer control over rate-distortion trade-offs. The widely used Lagrangian optimization technique is then applied to arrive at the optimally adjusted coefficients block. We show that such an optimization is very efficient for the second layer, but has little effect on the base layer. 相似文献
68.
The distributions of Hadamard coefficient for blocks of size 8 × 1 picture elements in six 625-line television pictures were obtained. The data were well approximated by gamma distributions. Low-sequency components were best fitted by choosing ?(n) with n in the range 1/2?2/3, and high-sequency components by n = 1 (equivalent to the negative exponential distribution). 相似文献
69.
70.