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141.
Anudeep K. Narula Beer Singh Sandhya Gupta Ramesh N. Kapoor 《Transition Metal Chemistry》1984,9(10):379-382
Summary Niobium(V) and tantalum(V) pentaethoxides react with monofunctional benzoyl hydrazones (BHy) in refluxing benzene to give products of the type, M(OEt)5–n(BHy)n (where M=Nb or Ta and n=1, 2 or 3). The complexes have been characterised on the basis of elemental analysis, spectral (i.r. and n.m.r.) and molecular weight data. 相似文献
142.
Using a 40 cm curved mica crystal spectrograph of the transmission type, the L spectrum of gadolinium has been investigated. The forbidden transition LIINII at λ = 1618.9 X.U. has been reported for the first time. 相似文献
143.
Carbon free Fe?Ni alloys (12 and 20 wt.% Ni) have been analysed by X-ray diffraction and surface Mössbauer spectroscopy (CXMS and CEMS) after boriding treatment at 1273 K for 20 hours. Some (Fe x Ni l-x )2B and Fe x Ni l-x B samples, with different values ofx, obtained by heating at 1073 K mixtures of elements in powder form, were used as reference. Besides (Fe x Ni l-x )2B and Fe x Ni l-x B, a third boride phase rich in boron has been detected in the outer borided layers of the alloy specimens. A third phase appears also in the corresponding X-ray patterns. A comparison between CXMS and CEMS data show that (Fe x Ni l-x )2B is present only in the deeper part of the borided layers and that the outer surface layer is a mixture of a nickel and boron rich boride and of a superparamagnetic oxide. 相似文献
144.
The present article reports a new optical method for real time addition or subtraction of two photographic images. Two transparencies which are placed in the two arms of a Mach-Zehnder interferometer with two orthogonal polarizers are subsequently added or subtracted by rotating an analyser inserted in the output beam. A linear combination of the amplitudes of the two images can also be observed for different orientations of the transmission axis of the analyser. Some experimental results are presented. 相似文献
145.
Studies of prompt radiations emitted in fission were started at Trombay in the late 1950’s by Dr R Ramanna and over the years
extensive investigations on the emission of prompt neutrons, gamma ray and K x-rays in fission were carried out with neutron
beams fromapsara andcirus reactors. In the early 1960’s studies on the emission of light-charged particles in fission, which is a rare mode of fission,
were also started. This paper reviews some of the recent studies on the emission of light-charged particles (lcp) in fission which were carried out with a view to investigate the mechanism oflcp emission, the scission configuration and the dynamics of the last stages of the fission process. 相似文献
146.
147.
148.
Ramesh Chander Kapoor 《Pramana》1976,7(5):334-343
Gravitational recoil of a gigantic black hole (M∼108–9 M⊙) formed in the nonspherical collapse of the nuclear part of a typical galaxy can take place with an appreciable speed as
a consequence of the anisotropic emission of gravitational radiation. Accretion of gaseous matter during its flight through
the galaxy results in the formation of a glowing shock front. The accompanying stellar captures can lead to the formation
of an accretion disk-star system about the hole. Consequently, the hole can become “luminous” enough to be observable after
it emerges out of the galaxy. The phenomenon seems to have an importance in relation to the observations of quasar-galaxy
association in a number of cases. 相似文献
149.
Fouad FS Wright JM Plourde G Purohit AD Wyatt JK El-Shafey A Hynd G Crasto CF Lin Y Jones GB 《The Journal of organic chemistry》2005,70(24):9789-9797
[structure: see text] The viability of proteins as targets of thermally and photoactivated enediynes has been confirmed at the molecular level. Model studies using a labeled substrate confirmed the efficacy of atom transfer from diyl radicals produced from enediynes to form captodatively stabilized carbon centered aminoacyl radicals, which then undergo either fragmentation or dimerization. To exploit this finding, a family of enediynes was developed using an intramolecular coupling strategy. Derivatives were prepared and used to target specific proteins, showing good correlation between affinity and photoinduced protein degrading activity. The findings have potential applications in the design of artificial chemical proteases and add to our understanding of the mechanism of action of the clinically important enediyne antitumor antibiotics. 相似文献
150.
A study of optogalvanic (OG) signals in a uranium hollow cathode discharge using a tunable pulsed dye laser with intensities above saturation revealed certain systematic trends. The peaks of OG signals, for a given hollow cathode current, due to all transitions involving the ground state are within a certain range of values. The same is true of the OG signals due to transitions involving the 620 cm-1 and 3800 cm-1 lower metastable levels. For all transitions involving the same lower state, the peaks of OG signal vary linearly with the discharge current. The slopes of such straight lines are different for transitions involving different lower levels of uranium. Effects of radiation trapping are seen in the OG signals due to transitions involving the ground state of uranium at currents above 60 mA. Details of our observations are presented and discussed. 相似文献