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91.
Rajkumar BJ Ramakrishnan V 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2001,57(2):247-254
The two methionine cations in the asymmetric part of the unit cell of bis(DL-methionine dihydrogen phosphate) have different conformations. This, together with the different environments seen by the two -CH2- groups in each skeleton cause several of the group wavenumbers to occur as doublets or as broad bands. The anion contains two dissimilar P-O bonds, which distorts the phosphate tetrahedron. Due to this, the stretching wavenumbers appear as doublets. There is extensive hydrogen bonding in the system in all three crystallographic directions and this is responsible for the changes in the position and intensity of several bands. Fermi resonance has also been observed. 相似文献
92.
We have postulated a novel pathway that could assist in the nucleation of soot particles through covalent dimerization and oligomerizations of a variety of PAHs. DFT calculations were performed with the objective of obtaining the relative thermal stabilities and formation probabilities of oligomeric species that exploit the facile dimerization that is known to occur in linear oligoacenes. We propose that the presence of small stretches of linear oligoacence (tetracene or longer) in extended PAH, either embedded or tethered, would be adequate for enabling the formation of such dimeric and oligomeric adducts; these could then serve as nuclei for the growth of soot particles. Our studies also reveal the importance of π‐stacking interactions between extended aromatic frameworks in governing the relative stabilities of the oligomeric species that are formed. © 2012 Wiley Periodicals, Inc. 相似文献
93.
Jin‐Baek Kim Ramakrishnan Ganesan So Young Yoo Jae‐Hak Choi Sang Yup Lee 《Macromolecular rapid communications》2006,27(17):1442-1445
Summary: A simple lithographic process in conjunction with a novel biocompatible nonchemically amplified photoresist material was successfully used for cell patterning. UV light irradiation on selected regions of the nonchemically amplified resist film renders the exposed regions hydrophilic by the formation of carboxylic groups. Mouse fibroblast cells were found to be preferentially aligned and proliferated on the UV light exposed regions of the nonchemically amplified resist film where carboxylic groups were present.
94.
A M Benial V Ramakrishnan R Murugesan 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2001,57(6):1199-1205
Infrared and laser Raman spectra of [Ni(II)(diars)2X]X, (X=Cl, Br and I) have been used as probes to determine the structures of chelated diarsine molecules. It has been observed that the effects of metal chelation and coordination geometry give rise to frequency shifts in these complexes. The variation in vibrational spectroscopic features indicates reduction in the symmetry of the complexes in the crystalline environment. The effect of halogen on the Ni-halogen stretching frequency of these square pyramidal complexes is not as significant as observed in the case of octahedral complexes. 相似文献
95.
A. Subbiah Pandi D. Velmurugan S. Shanmuga Sundara Raj Hoong‐Kun Fun V. Raghukumar V. T. Ramakrishnan 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(6):723-725
In the title compounds, C17H15N3 and C20H22N4, the methyl derivative crystallizes with two molecules in the asymmetric unit, while the N,N‐diethylamino derivative crystallizes with one molecule per asymmetric unit. The biphenyl twist angle for both molecular structures is approximately 45°. The molecular packing is stabilized by N—H?N hydrogen bonds. 相似文献
96.
The photochemical synthesis of 12H-benzothiazolo [2,3-b]quinazolin-12-ones (4) by the irradiation of 2-thioquinazolinediones 1 and disulphide 5 are described. 相似文献
97.
98.
M. B. Chadwick M. Hussein E. Ramakrishnan T. Baumann A. Azhari R. A. Kryger R. Pfaff M. Thoennessen S. Yokoyama J. R. Beene M. L. Halbert P. E. Mueller D. W. Stracener R. L. Varner G. van Buren R. J. Charity P-F. Hua D. G. Sarantites L. G. Sobotka 《Acta Physica Hungarica A》1995,2(3-4):347-353
New experimental data has been obtained for the208Pb(α, α′) reaction induced by 160 MeV alpha particles, for inelastic scattering to forward angles. We use these data to investigate the applicability of the multistep scattering theory of Feshbach, Kerman, and Koonin for describing this reaction. The mechanism we study, following the work of Gadioli et al. [1], is of the incident alpha particle remaining intact throughout the scattering process, exciting nucleon particle-hole pairs through multistep process. We conclude that this mechanism, combined with compound nucleus decay at low emission energies, can account for much of the observed data. However, there are indications that other processes also contribute at energies above the compound nucleus emission regime, and we outline future theoretical analyses that are needed. 相似文献
99.
The infrared and Raman spectra of crystalline samples of NdP5O14, NaNdP4O12 and KNdP4O12 are recorded. The spectra are analysed on the basis of vibrations of P=O, P-O, PO2 and P-O-P groups. The P4O
12
4−
ion has cyclic structures both in NaNdP4O12 and KNdP4O12 crystals. It has been inferred that the P-O-P bridges are stronger in metaphosphates. 相似文献
100.
Representations ofD
k
*
k
* for a quaternion division algebraD
k over a local fieldk are orthogonal representations. In this note we investigate when these orthogonal representations can be lifted to the corresponding
spin group. The results are expressed in terms of local root number of the representation. 相似文献