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排序方式: 共有1101条查询结果,搜索用时 78 毫秒
991.
Rajib K. Mitra Dr. Pramod K. Verma Dirk Wulferding Dirk Menzel Dr. Tamoghna Mitra Dr. Ana M. Todea Dr. Peter Lemmens Prof. Dr. Achim Müller Prof. Dr. Samir K. Pal Dr. 《Chemphyschem》2010,11(2):389-393
The effect of confinement and energy transfer on the dynamics of a molecular magnet, known as a model system to study quantum coherence, is investigated. For this purpose the well‐known polyoxovanadate [V15As6O42(H2O)]6? (V15) is incorporated into a protein (human serum albumin, HSA) cavity. Due to a huge overlap of the optical absorption spectrum of V15 with the emission spectrum of a fluorescence center of HSA (containing a single tryptophan residue), energy transfer is induced and probed by steady‐state and time‐resolved fluorescence. The geometrical coordination and the distance of the confined V15 to the tryptophan moiety of HSA are investigated at various temperatures. This effect is used as a local probe for the thermal denaturation of the protein at elevated temperatures. 相似文献
992.
Summary The problem of detection of multidimensional outliers is a fundamental and important problem in applied statistics. The unreliability
of multivariate outlier detection techniques such as Mahalanobis distance and hat matrix leverage has led to development of
techniques which have been known in the statistical community for well over a decade. The literature on this subject is vast
and growing. In this paper, we propose to use the artificial intelligence technique ofself-organizing map (SOM) for detecting multiple outliers in multidimensional datasets. SOM, which produces a topology-preserving mapping of
the multidimensional data cloud onto lower dimensional visualizable plane, provides an easy way of detection of multidimensional
outliers in the data, at respective levels of leverage. The proposed SOM based method for outlier detection not only identifies
the multidimensional outliers, it actually provides information about the entire outlier neighbourhood. Being an artificial
intelligence technique, SOM based outlier detection technique is non-parametric and can be used to detect outliers from very
large multidimensional datasets. The method is applied to detect outliers from varied types of simulated multivariate datasets,
a benchmark dataset and also to real life cheque processing dataset. The results show that SOM can effectively be used as
a useful technique for multidimensional outlier detection. 相似文献
993.
Stability analysis of peer-to-peer networks against churn 总被引:1,自引:0,他引:1
Users of the peer-to-peer system join and leave the network randomly, which makes the overlay network dynamic and unstable
in nature. In this paper, we propose an analytical framework to assess the robustness of p2p networks in the face of user
churn. We model the peer churn through degree-independent as well as degree-dependent node failure. Lately, superpeer networks
are becoming the most widely used topology among the p2p networks. Therefore, we perform the stability analysis of superpeer
networks as a case study. We validate the analytically derived results with the help of simulation.
相似文献
994.
995.
996.
Extensions of standard quantum mechanics with joint probability distributions for position coordinates and momenta have been
proposed in the literature. Time is assumed to be one-dimensional in these studies. In view of recent interest in two-dimensional
time, the construction is extended to this situation and found to satisfy the necessary consistency conditions. 相似文献
997.
Here we report the quasielastic neutron scattering and FTIR studies on the dynamics of propylene adsorbed in Na-Y and Na-ZSM5
zeolites. QENS data show that although the mechanism of translational motion of propylene is jump diffusion in both the cases
of Na-Y and Na-ZSM5 zeolites, the diffusivity is affected by the host size and is hindered in the case of Na-ZSM5. FTIR studies
showed that guest-host interaction in Na-ZSM5 is stronger than that in Na-Y zeolite corroborating the QENS results.
相似文献
998.
In this paper we propose a simple procedure to test the null hypothesis of exponentiality against the alternative that it belongs to the new worse then better than used in expectation (NWBUE) family. The test is shown to be consistent and the asymptotic distribution of the test statistic has been obtained. The performance of the test against various classes of alternatives has been studied by means of simulation. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
999.
K x‐ray satellites, hypersatellites and lines due to radiative Auger effect (RAE) of Ti, V, Cr, Mn and Fe were measured after exciting the samples with Ag bremsstrahlung at 35 kV. All the lines were measured with the ‘Spectroscan VY’ spectrometer of Spectron—OPTEL, Russia, in which a curved LiF(200) crystal was used. The spectra were deconvoluted using Voigt functions, and the peak positions of the satellites and hypersatellites were determined with errors of ± (1–5) eV. The energy shifts of the satellite lines with respect to their parent lines were also obtained. Multi‐configuration Dirac–Fock (MCDF) calculations with the inclusion of higher‐order corrections were carried out to predict the peak positions of the satellite and hypersatellite lines. Our data were then compared with our own calculated values and also with the data of others. Our measured energy shifts for KαL1, KαL2, Kαh and KβL1, when compared with our MCDF calculations, show a maximum deviation of 8, 12, 2 and 20% respectively. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
1000.
Abhas Mitra 《Pramana》2009,73(3):615-622
One of the outstanding puzzles of theoretical physics is whether quantum information indeed gets lost in the case of black
hole (BH) evaporation or accretion. Let us recall that quantum mechanics (QM) demands an upper limit on the acceleration of
a test particle. On the other hand, it is pointed out here that, if a Schwarzschild BH exists, the acceleration of the test
particle would blow up at the event horizon in violation of QM. Thus the concept of an exact BH is in contradiction with QM
and quantum gravity (QG). It is also reminded that the mass of a BH actually appears as an integration constant of Einstein
equations. And it has been shown that the value of this integration constant is actually zero! Thus even classically, there
cannot be finite mass BHs though zero mass BH is allowed. It has been further shown that during continued gravitational collapse,
radiation emanating from the contracting object gets trapped within it by the runaway gravitational field. As a consequence,
the contracting body attains a quasi-static state where outward trapped radiation pressure gets balanced by inward gravitational
pull and the ideal classical BH state is never formed in a finite proper time. In other words, continued gravitational collapse
results in an ‘eternally collapsing object’ which is a ball of hot plasma and which is asymptotically approaching the true
BH state with M = 0 after radiating away its entire mass energy. And if we include QM, this contraction must halt at a radius suggested by
the highest QM acceleration. In any case no event horizon (EH) is ever formed and in reality, there is no quantum information
paradox. 相似文献