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11.
A brief synthesis of endo-2-bromo-5-thiabicyclo [2.1.1]hexane ( 9 ) has been developed involving conversion of 3-cyclopentenol ( 6 ) to 3-thioacetoxycyclopentene ( 7 ), bromination of this giving trans-1,2-dibromo-4-thioacetoxycyclopentane ( 8 ), and treatment of the latter with base. Compound 9 is oxidized to its S-oxide 10 and S, S-dioxide 11 . Comparative 13C and 1H NMR data are given for 9–11 . 相似文献
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High-efficiency coupling structure for a single-line-defect photonic-crystal waveguide 总被引:1,自引:0,他引:1
Prather DW Murakowski J Shi S Venkataraman S Sharkawy A Chen C Pustai D 《Optics letters》2002,27(18):1601-1603
We present the design and fabrication of a planar structure for coupling light from a multimode feed waveguide into a single-line-defect photonic-crystal waveguide. Finite-difference time-domain calculations predict a coupling efficiency of greater than 90%, and preliminary experimental results indicate successful coupling through a single-line-defect photonic-crystal waveguide. Device design, fabrication, and characterization are presented. 相似文献
14.
Lin C Chen C Sharkawy A Schneider GJ Venkataraman S Prather DW 《Optics letters》2005,30(11):1330-1332
We present a promising coupling device, namely, a terahertz (THz) planar photonic crystal (PhC) lens based on the effective refractive-index contrast between the PhC and the surrounding unpatterned area. Three-dimensional finite-difference time-domain calculations show a 90% power transfer from a 100-microm silicon waveguide to a 10-microm waveguide, and 45% coupling efficiency is confirmed experimentally. These results demonstrate the utility of the PhC lens as an effective approach to coupling into PhC THz circuits. 相似文献
15.
N. Sankara Subramanian R. Vivek Sabaapathy P. Vickraman G. Vimal Kumar R. Sriram B. Santhi 《Ionics》2007,13(5):323-328
P-type porous silicon (PS) structure has been prepared by anodic electrochemical etching process under optimized conditions.
Photoluminescence studies of the PS structure show emission at longer wavelengths (red) for the excitation at 365 nm. Scanning
electron microscope investigations of the PS surface confirm the formation of uniform porous structure, and the pore diameter
have been estimated as 25 μm. Pd:SnO2/PS/p-Si heterojunction with top gold ohmic contact developed by conventional methods has been used as the sensor device.
Sensing properties of the device towards liquefied petroleum gas (LPG) and NO2 gas have been investigated in an indigenously developed sensor test rig. The response and recovery characteristics of the
sensor device at different operating temperatures show short response time for LPG. From the studies, maximum sensitivity
and optimum operating temperature of the device towards LPG and NO2 gas sensing has been estimated as 69% at 180 °C and 52% at 220 °C, respectively. The developed sensor device shows a short
response time of 25 and 57 s for sensing LPG and NO2 gases, respectively.
Paper presented at the Third International Conference on Ionic Devices (ICID 2006), Chennai, Tamilnadu, India, Dec. 7–9, 2006. 相似文献
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Raju Suresh Kumar Stephen Michael Rajesh Subbu Perumal Perumal Yogeeswari Dharmarajan Sriram 《Tetrahedron: Asymmetry》2010,21(11-12):1315-1327
Enantiomerically pure (R)-(1-phenylethyl)-3,5-bis[(E)-arylmethylidene]tetrahydro-4(1H)-pyridinones were synthesized for the first time, and their 1,3-dipolar cycloaddition with nitrile oxides affording di- and trispiroheterocycles regio- and stereoselectively in moderate yields was investigated. These compounds were evaluated against Mycobacterium tuberculosis H37Rv (MTB) and multi-drug-resistant M. tuberculosis (MDR-TB). Among the compounds screened, the dispiroheterocycle, namely, (5R,6R,10S)-3,9-bis(4-chlorophenyl)-10-(2,4-dichlorophenyl)-14-[(E)-(2,4-dichlorophenyl)methylidene]-12-[(R)-1-phenylethyl]-1,4,7-trioxa-2,8,12-tri-azadispiro[4.0.4.4]tetradeca-2,8-diene 5m was found to possess the maximum activity with MIC of 0.49 μM against MTB, being 9.6 and 15.6 times more potent than ciprofloxacin and ethambutol, respectively. Against MDR-TB, 5m displayed maximum activity with an MIC of 0.49 μM, with it thus being more active than rifampicin, isoniazid, ciprofloxacin and ethambutol by 7.8, 23, 77 and 124 times, respectively. 相似文献
18.
Kuldeep Sharma Gopal V. Pawar Sanjeev Giri Sriram Rajagopal Ramesh Mullangi 《Biomedical chromatography : BMC》2012,26(12):1589-1595
A highly sensitive, rapid assay method has been developed and validated for the estimation of bicalutamide in mouse plasma using liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the negative‐ion mode. The assay procedure involves extraction of bicalutamide and tolbutamide (internal standard, IS) from mouse plasma with a simple protein precipitation method. Chromatographic separation was achieved using an isocratic mobile phase (0.2% formic acid:acetonitrile, 35:65, v/v) at a flow rate of 0.5 mL/min on an Atlantis dC18 column (maintained at 40 ± 1°C) with a total run time of 3.0 min. The MS/MS ion transitions monitored were m/z 428.9 → 254.7 for bicalutamide and m/z 269.0 → 169.6 for IS. Method validation was performed as per FDA guidelines and the results met the acceptance criteria. The lower limit of quantitation achieved was 1.04 ng/mL and the linearity range extended from 1.04 to 1877 ng/mL. The intra‐ and inter‐day precisions were in the ranges of 0.49–4.68 and 2.62–4.15, respectively. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
19.
The effect of fluctuations in the two-variable discrete delay model proposed earlier by us [1] for the circadian rhythm of
the fungal species Neurospora Crassa is studied. We have investigated the effect of parametric and additive noise in two different regimes namely, steady-state
and Period-1 regimes. It is found that under the influence of noise coherent oscillations are generated in the steady-state.
Oscillations are preserved and robust to a wide range of noise intensity in the Period-1 regime. The oscillations in both
these regimes are always found to be close to the circadian period (21.5 h). Coherence resonance is observed when parametric
or velocity additive noise is added near the Hopf bifurcation. Finally, the implications of fluctuations in circadian rhythms
are discussed.
This article is dedicated to Professor Karl Jug on the occassion of his sixtyfifth birthday. 相似文献
20.