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1.
M Lepère R Gobeille V.Malathy Devi M.A.H Smith B Aoaeh A.W Mantz 《Journal of Molecular Spectroscopy》2004,224(1):7-12
We have analyzed the methyl fluoride RQ(J,0)Q branch lines located near 1475 cm−1 using a simultaneous multi-spectrum fitting technique. In this analysis we have used previously recorded diode-laser data in which we collected many data points covering only one or two Q branch lines in a particular run. The analysis consists of simultaneously fitting 57 spectra collected with numerous pressure and path length conditions for all absorption lines. The data are concatenated to create one continuous spectrum of the Q branch. We have determined the intensity and self-broadened widths at 296 K for 23 RQ(J,0) lines. 相似文献
2.
2-Formyl glycals undergo rapid condensation with arylhydrazines under solvent-free conditions to give the corresponding optically pure 4-substituted pyrazoles in good yields with high selectivity. The stereochemistry of the products was assigned by various NMR experiments. 相似文献
3.
Gowravaram Sabitha G.S.Kiran Kumar ReddyK.Bhaskar Reddy J.S. Yadav 《Tetrahedron letters》2003,44(34):6497-6499
The three component condensation of an aldehyde, a β-keto ester and urea (thiourea) in the presence of a catalytic amount of VCl3 is disclosed for the solution phase synthesis of dihydropyrimidinones. The ease of synthesis and work-up allowed the parallel synthesis of a 48-membered library of dihydropyrimidinones quickly and efficiently in good yields. 相似文献
4.
5.
Friedel-Crafts alkylation of indoles with epoxides to afford 3-alkyl indole derivatives at room temperature with moderate to good yields and high regioselectivity using nanocrystalline titanium(IV) oxide catalyst is described. 相似文献
6.
The effect of solar features on geospheric conditions leading to geomagnetic storms (GMSs) with planetary index,A
P ≥ 20 and the range of horizontal component of the Earth’s magnetic fieldH such that 250γ <H < 400γ has been investigated using interplanetary magnetic field (IMF), solar wind plasma (SWP) and solar geophysical data
(SGD) during the period 1978–99. Statistically, it is observed that maximum number of GMSs have occurred during the maximum
solar activity years of 21st and 22nd solar cycles. A peculiar result has been observed during the years 1982, 1994 when sunspot
numbers (SSNs) decrease very rapidly while numbers of GMSs increase. No distinct association between yearly occurrence of
disturbed days and SSNs is observed. Maximum number of disturbed days have occurred during spring and rainy seasons showing
a seasonal variation of disturbed days. No significant correlation between magnitude (intensity) of GMSs and importance ofH
α
, X-ray solar flares has been observed. Maximum number of GMSs is associated with solar flares of lower importance, i.e.,
SF during the period 1978-93.H
α
, X-ray solar flares occurred within lower helio-latitudes, i.e., (0–30)°N to (0–30)°S are associated with GMSs. NoH
α
, X-ray solar flares have occurred beyond 40°N or 40°S in association with GMSs. In helio-latitude range (10–40)°N to (10–40)°S,
the 89.5% concentration of active prominences and disappearing filaments (APDFs) are associated with GMSs. Maximum number
of GMSs are associated with solar flares. Coronal mass ejections (CMEs) are related with eruptive prominences, solar flares,
type IV radio burst and they occur at low helio-latitude. It is observed that CMEs related GMS events are not always associated
with high speed solar wind streams (HSSWSs). In many individual events, the travel time between the explosion on the Sun and
maximum activity lies between 58 and 118 h causing GMSs at the Earth. 相似文献
7.
Archana Devi 《European Polymer Journal》2007,43(6):2422-2432
Cardanol-based novolac-type phenolic resins were synthesized with different mole ratios of cardanol-to-formaldehyde, viz., 1:0.6, 1:0.7, and 1:0.8. These novolac resins were epoxidized with molar excess of epichlorohydrin at 120 °C in basic medium. The epoxidized novolac resins were, separately, blended with different weight ratios of carboxyl-terminated polybutadiene liquid rubber ranging between 0-25 wt% with an interval of 5 wt%. All the blends were cured at 150 °C with 40 wt% polyamide. The formation of various products during the curing of blend samples has been studied by Fourier-transform infra-red spectroscopic analysis. The tensile strength and elongation-at-break of the cured samples increased up to 15 wt% in the blend and decreased thereafter. This blend sample was also found to be most thermally stable system. The blend morphology, studied by scanning electron microscopy analysis, was finally correlated with the structural and property changes in the blends. 相似文献
8.
Protonation constant of an unsymmetrical Schiff base, salicylidene(N-benzoyl)glycyl hydrazone (SalBzGH), and formation constants
of its complexes have been determined potentiometrically at different temperatures in aqueous dioxane medium. Complexes of
SalBzGH with VO(IV), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) have been prepared. Elemental analyses, pH-metric,
molar conductance, magnetic susceptibility, electronic, IR, ESR, XRD (powder) and NMR studies have been carried out to study
the coordination behaviour of SalBzGH toward these metal ions. pH-metric and 1H NMR studies show the presence of two dissociable
protons in the ligand. IR and NMR spectra suggest the tridentate nature of the ligand, coordinating as a uninegative species
in the Mn(II) complex and as a dinegative species in all the other complexes. Presence of two different conformers of the
ligand at room temperature and stabilization of a single conformer upon complex formation have been established from1H NMR spectra of the metal-free ligand, Zn(II) and Hg(II) complexes recorded at 296 K. Electronic and ESR spectra indicate
highly distorted tetragonal geometry for VO(IV) and Cu(II) complexes. XRD powder patterns of the Zn(II) complexes are indexed
for an orthorhombic crystal system. 相似文献
9.
10.
Ranjana Yadav 《European Polymer Journal》2007,43(8):3531-3537
Models capable of predicting the maximum extent of conversion (p) of cardanol-based novolac-type phenolic resin, have been developed using response surface methodology to determine the optimum reaction conditions. Three-dimensional response surface and their contour plot were drawn. The maximum extent of conversion (98.93%) was predicted when the cardanol was condensed with formaldehyde (molar ratio 1:0.652) at 119.84 °C for a time period of 3 h with the catalyst (e.g., citric acid) concentration of 1.988% of total volume of cardanol and formaldehyde. The pH of the reaction mixture was maintained at 3.0. These predicted values for optimum process conditions were in good agreement with experimental data. 相似文献