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51.
52.
A new phthalic acid ester 1,2-benzenedicarboxylic acid bis(2S-methyl heptyl) ester (1) was isolated from the hexane extract of the whole plant of Ajuga bracteosa. In addition, chloroform and methanol extracts yielded neo-clerodane diterpene ajugarin-I and two iridoid glycosides, reptoside and 8-O-acetyl harpagide. The structures of all the compounds were confirmed by extensive spectroscopic analysis. From the two oily fractions nine and six volatile constituents respectively were identified by GCMS. Linalyl acetate was found to be common in both the oil fractions. This plant is a new source of linalyl acetate, a valuable perfumery compound. 相似文献
53.
An electric-field poling process was established that yielded uniform periodically poled lithium niobate (PPLN) in 0.5 mm
thick lithium niobate substrate. We have fabricated 50 mm long fanned as well as multigrating PPLNs having period variations
from 25 μm to 32 μm. These PPLNs are required for quasi-phase-matched (QPM) optical parametric oscillator (OPO) applications.
We have also configured a bench-top OPO set-up based on these PPLNs. 相似文献
54.
Prasenjit Mandal Rupali Kaul Tarun Jain 《European Journal of Operational Research》2018,264(1):181-199
In this paper, we study the newsvendor’s pricing and stocking decisions under reference point effects. The demand faced by the newsvendor is endogenous and the customers may also decide to procure the product from an outside option. We characterize the firm’s optimal pricing and stocking decisions. Our analysis reveals a threshold policy on the firm’s ordering and pricing decisions while considering the impact of reference point effects. We also find that as the level of optimism increases, the firm’s optimal ordering level decreases and optimal price increases. We further study the impact of loss aversion on the firm’s ordering and pricing decisions. 相似文献
55.
A. Kaul 《Isotopes in environmental and health studies》2013,49(2):54-59
The calculation of the dose rate and cumulative dose in the morrow-free skeleton and bone marrow of thorotrast patients presupposes the knowledge of both the translocation of thorium daughters to the skeleton, and the portion of 232Th that is localized in colloidal form in the bone marrow. Whereas in bon marrow 228Th is in equilibrium with 232Th up to only 20%, in marrow-free skeleton 228Th is present in excess to 232Th (average activity ratio 1·75), considering the measured activity ratios between 232Th and its daughters as well as the distribution of the colloid and the unclides of the thorium decay chain within the organism the dose rate and cumulative dose in bone marrow and marrow-free bone were calculated as function of the time of thorotrast burden and the amount of injected material. 相似文献
56.
Harris R Johnson MW Han S Berkley AJ Johansson J Bunyk P Ladizinsky E Govorkov S Thom MC Uchaikin S Bumble B Fung A Kaul A Kleinsasser A Amin MH Averin DV 《Physical review letters》2008,101(11):117003
Macroscopic resonant tunneling between the two lowest lying states of a bistable rf SQUID is used to characterize noise in a flux qubit. Measurements of the incoherent decay rate as a function of flux bias revealed a Gaussian-shaped profile that is not peaked at the resonance point but is shifted to a bias at which the initial well is higher than the target well. The rms amplitude of the noise, which is proportional to the dephasing rate 1/tauphi, was observed to be weakly dependent on temperature below 70 mK. Analysis of these results indicates that the dominant source of low energy flux noise in this device is a quantum mechanical environment in thermal equilibrium. 相似文献
57.
Chemical investigations on the stem bark of Holarrhena antidysenterica resulted in the isolation of a new steroidal alkaloid designated as holadysenterine (1), together with three known steroidal alkaloids, conessine (2), isoconessimine (3) and kurchessine (4). Their structures were elucidated on the basis of 1D- and 2D-NMR techniques and high-resolution mass spectrometry. 相似文献
58.
59.
Pamita Bhandari Neeraj Kumar Bikram Singh Ajai P. Gupta Vijay K. Kaul Paramvir S. Ahuja 《Chromatographia》2009,69(3-4):221-227
A liquid chromatography method was developed and validated for the determination of picroside-I and picroside-II in herbal preparations containing Picrorhiza kurroa as one of the ingradients. Resolution of picrosides was achieved on a reversed phase (C-18) endcapped bidentate column by using a mobile phase of acetonitrile: water (25:75 v/v). The detection of picrosides was carried out at 270 nm. The method was validated for precision, accuracy and robustness according to the International Conference on Harmonization (ICH) guidelines and is applicable for the quality control of preparations containing P. kurroa. Analysis of samples in forced degradation proved it to be applicable for stability evaluation. The linear regression analysis data showed good linear relationship (r 2 = 0.9999 ± 0.0010 for picroside-I and 0.9997 ± 0.0012 for picroside-II) in the concentration range of 0.4–4.0 μg. The limit of detection and quantification for picroside-I and picroside-II were recorded to be 28.1 and 73.1 ng and 85.2 and 221.5 ng, respectively. Satisfactory recovery results were observed from the herbal preparations (97.5–100.5%). Intra- and inter- day precision of the method was acceptable, with relative standard deviation (%RSD) values in the range of 0.04–1.16% and 0.03–0.27%, respectively. 相似文献
60.
N. A. Babushkina A. N. Taldenkov S. V. Streltsov A. V. Kalinov T. G. Kuzmova A. A. Kamenev A. R. Kaul D. I. Khomskii K. I. Kugel 《Journal of Experimental and Theoretical Physics》2014,118(2):266-278
We study experimentally and theoretically the effect of Eu doping and partial oxygen isotope substitution on the transport and magnetic characteristics and spin-state transitions in (Pr1 ? y Eu y )0.7Ca0.3CoO3 cobaltites. The Eu doping level y is chosen in the range of the phase diagram near the crossover between the ferromagnetic and spin-state transitions (0.10 < y < 0.20). We prepared a series of samples with different degrees of enrichment by the heavy oxygen isotope 18O, namely, with 90, 67, 43, 17, and 0% of 18O. Based on the measurements of the ac magnetic susceptibility χ(T) and electrical resistivity ρ(T), we analyze the evolution of the sample properties with a change of the Eu and 18O content. It is demonstrated that the effect of increasing the 18O content on the system is similar to that of increasing the Eu content. The band structure calculations of the energy gap between t 2g and e g bands including the renormalization of this gap due to the electron-phonon interaction reveals the physical mechanisms underlying this similarity. 相似文献