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101.
Mrinmay Pal Somnath Bandyopadhyay Palas Biswas Rimlee Debroy M. C. Paul Ranjan Sen Kamal Dasgupta S. K. Bhadra 《Optical and Quantum Electronics》2007,39(14):1231-1243
In this paper, gain flatness is studied for simultaneous 16-ITU-T channel amplifications at C-band (1,532–1,558 nm) in a single
stage EDFA for WDM application at different average inversion levels. The inversion levels are varied due to the change of
the input signal levels from the targeted operating point and also for dropping few numbers of channels. Specially designed
gain flattening filter (GFF) is used in order to get the flat gain with gain variation ±0.5 dB for −20 dBm/ch input signal
power (total input signal power is −8.0 dBm) at a fixed average inversion level which is maintained by proper selection of
optimum fibre length and pump power. A specific loss spectrum of GFF is obtained by writing a chirped fibre Bragg grating
of length 20 mm. Gain variations are studied by changing the total input signal levels from −8.0 dBm to −20.0 dBm and maintained
within 20.0 ± 0.5 dB by using automatic gain control (AGC) circuit. About 15 out of 16 channels are dropped and observed ±
0.5 dB gain-variation which is an important parameter in optical network system. 相似文献
102.
In this paper, 10 Gbps optical soliton transmission link using in-line semiconductor optical amplifiers (SOAs) for already installed standard single mode fibers (SMF) at 1.3 μm wavelength has been reported. The pattern effect and the impact of chirp on pulse propagation after amplification have been investigated. The observations are based on modeling and simulation optical soliton transmission link. Optical soliton pulse transmission over distances of the order of several hundreds of kilometers has been shown with and without initial chirp. 相似文献
103.
An experimental and computational investigation into the autoignition of methanol under high‐pressure and low‐to‐intermediate temperature conditions is conducted. The ignition delay results have been obtained using a heated rapid compression machine, over a pressure range of 7–30 bar, a temperature range of 850–1100 K, and an equivalence ratio range of 0.25–2.0. Using kinetic schemes recently reported in the literature for the combustion of methanol, the experimental results are compared to computationally obtained values. The kinetic schemes studied are found to significantly underpredict ignition delays for the conditions investigated. A sensitivity analysis of the computed results to reaction rate constants is also conducted. It is shown that the reaction of methanol with HO2 radical is critical to the predicted values of ignition delays under the current experimental conditions. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 43: 175–184, 2011 相似文献
104.
105.
106.
Ahmed Kamal J. Surendranadha Reddy E. Vijaya Bharathi D. Dastagiri 《Tetrahedron letters》2008,49(2):348-353
A mild and efficient procedure has been developed for the monosulfonylation of various amines using mesyl or tosyl chlorides in water at room temperature to afford the corresponding sulfonamides in high yields. 相似文献
107.
108.
Remon M. Zaki Adel M. Kamal El-Dean Jehan A. Mickey Nermin A. Marzouk Rasha H. Ahmed 《合成通讯》2017,47(24):2406-2416
Ethyl 4,6-dimethyl-3-(pyrrol-1-yl) selenolo[2,3-b]pyridine-2-carboxylate (2) was synthesized by the reaction of previously prepared ethyl 3-amino-4,6-dimethyl selenolo[2,3-b]pyridine-2-carboxylate (1) with 2,5-dimethoxytetrahydrofuran in acetic acid. The pyrrolyl ester (2) was converted into the corresponding carbohydrazide 3 which reacted with acetyl acetone, aromatic aldehydes, carbon disulfide in pyridine, and sodium nitrite to afford the corresponding dimethyl pyrazolyl 4, arylidene carbohydrazides 5a–d, oxadiazolyl thiole 6, and caboazide compound 8, respectively. The carboazide 8 reacted with different alcohols and amines to give the corresponding carbamates 9a–c and the aryl urea derivatives 10a–d. Heating of carboazide 8 in dry xylene afforded the pyridoselenolo-pyrrolopyrazinone 11. The latter compound was used as a versatile starting precursor for synthesis of other pyridoselenolo-pyrrolopyrazine compounds. The newly synthesized compounds and their derivatives were characterized by elemental analysis and spectroscopy (IR, 1H-NMR, and mass spectra). Some of the newly synthesized pyrrolyl selenolopyridine compounds showed remarkable antioxidant activity compared to ascorbic acid. 相似文献
109.
A hybrid catalyst has been prepared by incorporating sulfonic acid onto cobalt ferrite magnetic nanoparticles. The catalyst was successfully applied for rapid (20?min) synthesis of α,α-dibromoketones directly from alkynes and NBS. The reaction works well in the presence of 10?wt% of the catalyst at room temperature to produce the desired products in high yield. The catalyst could be recovered using an external magnet and reused without appreciable change in activity. 相似文献
110.
Srinivas Angapelly P.V. Sri Ramya Routhu SunithaRani C. Ganesh Kumar Ahmed Kamal Mohammed Arifuddin 《Tetrahedron letters》2017,58(49):4632-4637
A simple and expedient multicomponent protocol was developed to synthesize 4-thiazolidinones by employing VOSO4 as a catalyst under ultrasonic irradiation. The significant features of this protocol includes shorter reaction time, high yields, low catalyst loading, and also the catalyst can be recovered and reused up to next four cycles without significant loss in catalytic activity. All the synthesized novel indazole compounds were evaluated for their antibacterial and anti-biofilm activities. Compounds 9n, 9o and 9q showed promising activity (MIC value of 3.9?µg/mL) against K. planticola (MTCC 530). They also exhibited significant bactericidal activity against K. planticola (MTCC 530) (MBC value of 15.6?µg/mL). Additionally, 9n, 9o and 9q inhibited biofilm formation (IC50 values ranging between 20.28–20.79?μg/mL) in this organism. 相似文献