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91.
Tripathi V.K. Liu C.S. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1990,18(3):466-471
The introduction of a plasma and a strong guide magnetic field in a free electron laser (FEL) slows down the phase velocity of radiation, significantly reducing the requirements on beam energy for generating frequencies below the electron-cyclotron frequency (ω1≲ωc). Around plasma resonance (ω1~ωp), the FEL mode couples to two-stream instability (TSI), attaining a large growth rate, comparable to that of the wiggler-free TSI. At plasma densities comparable to beam density, the beam-induced local depression in the electron density of the plasma acts as a waveguide for guiding any high-frequency radiation when the beam current is ≳17 kA 相似文献
92.
Brajesh Pandey Amita Tripathi R. P. Tripathi H. C. Verma 《Hyperfine Interactions》2005,166(1-4):537-542
Mössbauer spectroscopic studies of two sedimentary layers from Petriccio section in Gubbio formation are presented. It is found that these layers have almost the same iron phases nanophase hematite and phyllosilicate and with the same compositions as those in the Cretaceous-Tertiary Boundary (KTB) in Petriccio. The two layers also show enhancement in the siderophile elements such as Cr, Ni, Fe, Ca etc. to that found in the KTB layer. The two layers are well separated from the KTB layer, 128 and 149 cm below this layer, and show no enhancement of iridium. From the data it is suggested that the two layers also represent some kind of impact by extraterrestrial (ET) bolides. 相似文献
93.
An efficient fast Fourier transform method has been employed to determine correlation function [g(r*)] using the structure factor [S(Q*)] calculated with the rescaled mean spherical approximation (RMSA) and the DLVO potential. Based on this function a parametric
(size and charge) study of the ordering in a highly charged and concentrated macroions (an ideal colloid) has been made. The
strength of the correlation increases with the increase in the charge on macroions and it saturates after acertain value.
Similarly, a critical diameter of the particle depending on the charge on it has been found at which normal feature of the
ordering disappears. 相似文献
94.
The Anderson-Grüneisen parameter δ has been computed theoretically from a general expression developed by Sharma and Tripathi[6]. The δ-γ (Grüneisen parameter) curves have been plotted to find a relation for the best fitted yielding curves by the method of least squares. The relation developed can be put as δ = AγB and it can be inferred that chang's[3] relation is a particular case of this general equation. 相似文献
95.
The photo (PL) and electro (EL) luminescence in ZnS: MnLa and ZnS: La have been studied. The enhancement and quenching of
emission bands have been observed on the simultaneous application of sinusoidal field and photons. The wave shape, voltage,
frequency and temperature dependence of EL brightness have been reported. A study of the phosphorescence and thermoluminescence
of these phosphors is also carried out and it is observed that the trap-depth changes slowly with temperature and activator
concentration. An attempt has been made to calculate the trap depth by studying temperature dependence of EL brightness. The
results are reported and discussed. 相似文献
96.
Titanium(IV) alkyl xanthates of the types CpTi(S2COR)Cl2, CpTi(S2COR)2Cl and CpTi(S2COR)3, where R = CH3, C2H5, C3H7, C4H9 and C5H11, have been prepared by the reaction of monocyclopentadienyl titanium(IV) trichloride with potassium alkyl xanthates in anhydrous dichloromethane. Conductance and infrared studies suggest that these complexes are non-electrolytes in which all of the xanthate ligands are bidentate. Proton nmr spectra of these complexes indicate that there is rapid rotation of the cyclopentadienyl ring about the metal-ring axis and for the CpTi(S2COR)3 complexes non-equivalence of the alkylxanthate ligands was observed. 相似文献
97.
Using hodograph and Legendre transformation functions the basic equations are recast in terms of this function, and the conditions which this function should satisfy are stated. Several applications of this method are considered, and the geometry of magnetic field lines is discussed. 相似文献
98.
D. B. Parihar Om Prakash Indira Bajaj R. P. Tripathi K. K. Verma 《Mikrochimica acta》1971,59(3):393-398
Summary High explosives having the sameR
f
values on a thin-layer chromatogram and difficult to separate are readily resolved as their coloured -complexes with aromatic amines. After liberation from their complexes on the plate, up to 1.5 g of the explosives can be conveniently estimated at their characteristic absorption maxima.
Zusammenfassung Hochexplosive Substanzen mit gleichenR f -Werten auf Dünnschichtchromatogrammen, die sich schlecht trennen lassen, werden als gefärbte -Komplexe mit aromatischen Aminen gut voneinander getrennt. Nach Freisetzung aus den Komplexen auf der Platte können bis zu 1,5 g der Explosivstoffe bei ihrem charakteristischen Absorptionsmaximum auf übliche Weise bestimmt werden.相似文献
99.
Sandeep Mishra Sarvpreet Kaur S. K. Tripathi C. G. Mahajan G. S. S. Saini 《Journal of Chemical Sciences》2006,118(4):361-369
We present here infrared absorption spectra of dithia tetraphenylporphine and its cation in the 450–1600 and 2900–3400 cm−1 regions. Most of the allowed IR bands are observed in pairs due to overallD
2h
point group symmetry of the molecule. The observed bands have been assigned to the porphyrin skeleton and phenyl ring modes.
Some weak bands, which are forbidden underD
2h
, also appear in the spectra due to the distortion of the molecule from planarity-caused by the out-of-plane positioned N
and S atoms. Increased intensity of some phenyl ring bands compared to free-base tetraphenylporphine is explained on the basis
of rotation of phenyl rings towards the mean molecular plane. Contrary to the point group symmetry of cation of dithia tetraphenylporphine,
certain bands are observed to be degenerate due to identical bonding arrangements in pyrrole rings of the cation 相似文献
100.
Ramachandran K. Tripathi V.K. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1998,26(2):141-144
Near the critical layer, a large-amplitude laser beam creates a transverse plasma channel due to the ponderomotive force. The axis of the channel is normal to the ambient density gradient. Inside the channel, the laser beam decays into counter-propagating ion acoustic and Langmuir waves. A nonlocal theory of the process is developed for a parabolic density profile. The growth rate of the instability is significantly reduced due to the nonlocal effects 相似文献