نتایج جستجو برای: coherence time
تعداد نتایج: 1947392 فیلتر نتایج به سال:
The problem of electronic energy transfer in a network of two-level systems coupled to a single trapping site is investigated using a simple Haken-Strobl model with diagonal disorder. The goal is to illustrate how the trapping time T(trap), coherence time T(d), and molecular topology all affect the overall efficiency of a light-harvesting network. Several issues are identified that need to be c...
The channel coherence time in indoor WLANs normally exceeds multiple frame transmission times. In light of this, we propose a new rate adaptation scheme, termed as the Rate Adaptation using Coherence Time (REACT), that has the following key features. First, without exchanging RTS and CTS frames, the receiver in REACT informs the transmitter of the improved channel condition via altering the ACK...
We have measured the decay of NMR multiple quantum coherence intensities both under the internal dipolar Hamiltonian as well as when this interaction is effectively averaged to zero, in the cubic calcium fluoride CaF2 spin system and the pseudo-one-dimensional system of fluoroapatite. In calcium fluoride the decay rates depend both on the number of correlated spins in the cluster, as well as on...
We present a method for the testing of significance when evaluating the coherence of two oscillatory time series that may have variable amplitude and frequency. It is based on evaluating the self-correlations of the time series. We demonstrate our approach by the application of wavelet-based coherence measures to artificial and physiological examples. Because coherence measures of this kind are...
The electrophysiological brain activities are nonlinear in nature as measured by Electroencephalography (EEG). There are coherent activities in brain not only seen during explicit tasks but also during rest. This article aims to employ most robust nonlinear dynamics Time Frequency representation (TFR) techniques such as wavelet phase coherence to investigate brain activity in different frequenc...
This presentation is about (i) formal, (ii) synchronic, (iii) epistemic (iv) coherence (v) requirements. (i) Formal coherence is to be distinguished from other sorts of coherence discussed in contemporary epistemology (e.g., in some empirical, truth/knowledge-conducive sense [1]). Ideally, whether a set of judgments is coherent (in the present sense) should (in principle) be determinable a prio...
An analytical expression for the self coherence function of a microcavity and partially coherent source is derived from first principles in terms of the component self coherence functions. Excellent agreement between the model and experimental measurements of two Resonant Cavity LEDs (RCLEDs) is evident. The variation of coherence length as a function of numerical aperture is also described by ...
An analytical model derived from normal mode theory for the accumulated effects of range-dependent multiple forward scattering is applied to estimate the temporal coherence of the acoustic field forward propagated through a continental-shelf waveguide containing random three-dimensional internal waves. The modeled coherence time scale of narrow band low-frequency acoustic field fluctuations aft...
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. An analytical model derived from normal mode theory for the accumulated effects of range-dependent multiple forward...
PURPOSE We evaluated the feasibility of using optical coherence tomography and optical coherence microscopy technology to assess human kidney morphology. MATERIALS AND METHODS A total of 35 renal specimens from 19 patients, consisting of 12 normal tissues and 23 tumors (16 clear cell renal cell carcinomas, 5 papillary renal cell carcinomas and 2 oncocytomas) were imaged ex vivo after surgical...
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