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151.
152.
R. Venkateswarlu V. U. M. Rao K. Pavan Kumar 《International Journal of Theoretical Physics》2008,47(3):640-648
We have studied the problem of cosmic strings for Bianchi-I, II, VIII and IX string cosmological models in Barber’s (Gen.
Relativ. Gravit. 14:117, 1982) second self—creation theory of gravitation. We have obtained some classes of solutions by considering different functional
form for metric potentials. It is also observed that due to the presence of scalar field, the power index ‘m’ of the metric coefficients has a range of values. 相似文献
153.
L. V. KrishnaRao D. V. Sathish Ch. Venkata Reddy U. S. Udayachandran Thampy K. Venkateswarlu P. S. Rao R. V. S. S. N. Ravikumar 《Applied magnetic resonance》2012,42(3):403-411
The Cr3+-doped cadmium oxide nanopowder is prepared at room temperature by a mild and simple solution method. The prepared powder
is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), optical, electron paramagnetic resonance
(EPR) and Fourier transform infrared (FT-IR) techniques. The XRD powder pattern reveals the lattice structure and cell parameters
are evaluated. The SEM image shows the stone-like morphology of the nanopowder. The optical absorption spectrum indicates
the distorted octahedral site symmetry of Cr3+ ions. The crystal field Dq and interelectronic repulsion parameters B and C are evaluated. The EPR spectrum gives a resonance signal at g = 1.973 for Cr3+ ions. The FT-IR spectrum reveals the characteristic vibrations of cadmium oxide. 相似文献
154.
Upper and lower bounds on the drag offered to a Newtonian fluid sphere placed in an Ellis model fluid in creeping flow have been found using variational principles. For a solid sphere, the bounds are in good agreement with those reported by earlier investigators. 相似文献
155.
K. Srihari Babu M. Raghavendar Rao G. Goverdhan P. Srinivas P. Pratap Reddy G. Venkateswarlu 《合成通讯》2013,43(13):1751-1758
Valganciclovir hydrochloride (1) is used for the treatment of cytomegalovirus (CMV) retinitis in patients with weakened immune systems. Valganciclovir hydrochloride is a hydrochloride salt of L-valyl ester of ganciclovir (2) that exists as a mixture of two diastereomers. According to the U.S. Food and Drug Administration specifications, the diastereomeric ratio of valganciclovir hydrochloride 1 should be maintained in the range 55:45 to 45:55. According to the U.S. Food and Drug Administration specifications, the diastereomeric ratio of valganciclovir hydrochloride 1 should be maintained in the range 55:45 to 45:55. During the process development of valganciclovir hydrochloride, six related substances (impurities) were observed along with the final active pharmaceutical ingredient. Among these six impurities, ganciclovir (2) and guanine (3) are the key starting materials and degraded impurities of ganciclovir, respectively. The remaining four impurities were identified as isovalganciclovir hydrochloride (4), methoxymethylguanine (5), O-acetoxy ganciclovir (6), and isovalarylganciclovir (7). The present work describes the synthesis and characterization of these four impurities. 相似文献
156.
Mukka Satish Kumar Marri Venkateswarlu Purugula Venkanna Pondichery Kuppuswamy Saiprakash 《合成通讯》2013,43(19):2251-2258
An efficient and safe method for nitration of aromatic compounds and decarboxylative nitration of α,β-unsaturated acids was developed using trichloroisocyanuric acid (TCICA)/dimethylformamide (DMF) in the presence of NaNO2. The reaction times of conventional protocol reduced from 8–10 h to 1.0–1.5 h (60–90 min) under sonication, even though the yields are comparable under both the conditions. 相似文献
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