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排序方式: 共有115条查询结果,搜索用时 31 毫秒
81.
82.
Kushal C. Lekhok Debajyoti Bhuyan Dipak Prajapati Romesh C. Boruah 《Molecular diversity》2010,14(4):841-846
An environmentally friendly and highly efficient procedure for the preparation of quinolines and fused polycyclic quinolines
has been developed by a simple Friedlander annulation reaction of 2-aminoaryl ketone with carbonyl compounds in presence of
zinc triflate under microwave irradiation and solvent-free conditions. The reaction also proceeds effectively when In(OTf)3 was used in lieu of Zn(OTf)2 as the catalyst. The catalyst can be recovered after the reaction and reused efficiently in subsequent runs. 相似文献
83.
In this study, we investigate the characteristics of the total columnar ozone (TCO) over Dibrugarh (27.3° N and 94.6° E),
India for the period September 2007 to February 2009 using Microtops II Ozonometer. These measurements are compared with TCO
data available from Total Ozone Mapping Spectrometer (TOMS) on board Nimbus-7 satellite for the same period. It has been observed
that the TCO increases from morning till noon and then decreases rapidly in the afternoon. A distinct seasonal variation of
TCO is observed with low value in the months of September–December and high values in the month of April, May and June as
seen from both Microtops II and TOMS measurements. Satellite observations reveal that the TCO at all latitudes is nearly equal
in the months of September–November and May to August. The seasonal variation of TCO between December to May is nearly a mirror
image between low and mid latitudes along the three longitudes sectors. 相似文献
84.
Anisimovsky VV Artamonov AV Bassalleck B Bhuyan B Blackmore EW Bryman DA Chen S Chiang IH Christidi IA Cooper PS Diwan MV Frank JS Fujiwara T Hu J Ivashkin AP Jaffe DE Kabe S Kettell SH Khabibullin MM Khotjantsev AN Kitching P Kobayashi M Komatsubara TK Konaka A Kozhevnikov AP Kudenko YG Kushnirenko A Landsberg LG Lewis B Li KK Littenberg LS Macdonald JA Mildenberger J Mineev OV Miyajima M Mizouchi K Mukhin VA Muramatsu N Nakano T Nomachi M Nomura T Numao T Obraztsov VF Omata K Patalakha DI 《Physical review letters》2004,93(3):031801
An additional event near the upper kinematic limit for K+-->pi(+)nunu; has been observed by experiment E949 at Brookhaven National Laboratory. Combining previously reported and new data, the branching ratio is B(K+-->pi(+)nunu;)=(1.47(+1.30)(-0.89))x10(-10) based on three events observed in the pion momentum region 211
相似文献
85.
H. Bhuyan M. Favre G. Avaria H. Chuaqui E. Wyndham M. Paulraj 《Applied Surface Science》2007,254(1):197-200
We have performed an experimental analysis on the investigation of high energy ion beam irradiation on Si(1 0 0) substrates at room temperature using a low energy plasma focus (PF) device operating in methane gas. The surface modifications induced by the ion beams are characterized using standard surface science diagnostic tools, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), photothermal beam deflection, energy-dispersive X-ray (EDX) analysis and atomic force microscope (AFM) and the results are reported. In particular, it has been found that with silicon targets, the application of PF carbon ion beams results in the formation of a surface layer of hexagonal (6H) silicon carbide, with embedded self-organized step/terrace structures. 相似文献
86.
Zhou SZ Sey M De Clercq PJ Milanesio M Viterbo D 《Angewandte Chemie (International ed. in English)》2000,39(16):2861-2863
87.
Gunter S Wolf RC Leuterer F Gruber O Kaufmann M Lackner K Maraschek M Mc Carthy PJ Meister H Peeters A Pereverzev G Salzmann H Schade S Schweinzer J Suttrop W 《Physical review letters》2000,84(14):3097-3100
Internal transport barriers have been demonstrated to exist also under conditions with T(e) approximately T(i) approximately 10 keV and predominant electron heating of the tokamak core region. Central electron cyclotron heating was added to neutral beam injection-heated ASDEX Upgrade discharges with a preexisting internal transport barrier, established through programmed current ramping leading to shear reversal. Compared to a reference internal transport barrier discharge without electron cyclotron resonance heating, the electron heat conductivity in the barrier region was found not to increase, in spite of a fivefold increase in electron heat flux, and also angular momentum and ion energy transport did not deteriorate. 相似文献
88.
Calderbank AR; Cameron PJ; Kantor WM; Seidel JJ 《Proceedings London Mathematical Society》1997,75(2):436-480
When m is odd, spreads in an orthogonal vector space of type+(2m + 2,2) are related to binary Kerdock codes and extremalline-sets in 2m + 1 with prescribed angles. Spreads in a 2m-dimensionalbinary symplectic vector space are related to Kerdock codesover Z4 and extremal line-sets in with prescribed angles. These connections involve binary, realand complex geometry associated with extraspecial 2-groups.A geometric map from symplectic to orthogonal spreads is shownto induce the Gray map from a corresponding Z4-Kerdock codeto its binary image. These geometric considerations lead tothe construction, for any odd composite m, of large numbersof Z4-Kerdock codes. They also produce new Z4-linear Kerdockand Preparata codes. 1991 Mathematics Subject Classification:primary 94B60; secondary 51M15, 20C99. 相似文献
89.
Deep Jyoti Bhuyan Quan V. Vuong Anita C. Chalmers Ian A. van Altena Michael C. Bowyer Christopher J. Scarlett 《Chemical Papers》2016,70(5):567-575
Eucalyptus species have found their place in traditional medicine and pharmacological research and they have also been shown to possess a large number of phenolic compounds and antioxidants. The present study sought to implement conventional extraction to yield maximal total phenolic content (TPC), total flavonoid content (TFC), proanthocyanidins, antioxidants, and saponins from E. robusta using different solvents. The most suitable extraction solvent was further employed for extracting phytochemicals from E. saligna, E. microcorys, and E. globulus to select the Eucalyptus species with the greatest bioactive compound content. The results emphasised the efficiency of water in extracting TPC ((150.60 ± 2.47) mg of gallic acid equivalents per g), TFC ((38.83 ± 0.23) mg of rutin equivalents per g), proanthocyanidins ((5.14 ± 0.77) mg of catechin equivalents per g), and antioxidants ABTS ((525.67 ± 1.99) mg of trolox equivalents (TE) per g), DPPH ((378.61 ± 4.72) mg of TE per g); CUPRAC ((607.43 ± 6.69) mg of TE per g) from E. robusta. Moreover, the aqueous extract of E. robusta had the highest TPC, TFC and antioxidant values among the other Eucalyptus species tested. These findings highlighted the efficiency of conventional extraction in extracting natural bioactive compounds from Eucalyptus species for pharmaceutical and nutraceutical applications. 相似文献
90.
The apparent and limiting apparent molal volumes of dilute aqueous solutions of K3[Al(ox)3] · 3H2O, K3[Fe(ox)3] · 3H2O, K3[Co(ox)3] · 3H2O, and K3[Cr(ox)3] · 3H2O complexes were determined from density data measured at 15°, 25°, and 35°C. The apparent and limiting apparent molal adiabatic
compressibilities of these complexes were determined from measured ultrasonic sound velocities at 15°, 25°, and 35° in dilute
aqueous solutions. The volume change associated with complex formation is discussed in terms of the nature of the coordinate
bond and the overall hydration behavior of these complexes. 相似文献