Width Of Time Window Research Articles

Soliton collision and Raman gain regimes in continuous-wave pumped supercontinuum generation

We numerically investigate supercontinuum generation using continuous-wave pumping. It is found that energy transfer during collision of solitons plays an important role. The relative influence of Raman gain on spectral broadening is shown to depend on the width of the calculation time window. Our results indicate that increasing the spectral linewidth of the pump can decrease the supercontinuum spectral width. Using a fiber with smaller dispersion at the pump wavelength reduces the required fiber length by decreasing the temporal width of the solitons formed from modulation instability. This also reduces the sensitivity to the pump spectral linewidth.

Analysis of the reliability and resolution of the earthquake source history inferred from waveforms, taking the Chi-Chi earthquake as an example

In the inversion of observed waveforms to obtain the earthquake source faulting process some uncertain factors may influence the reliability of the results. Several numerical tests have been analysed in this paper in order to understand the effect of some of these uncertain parameters, such as the number and width of multiple time windows that define the source-time function, the assumed strike and dip of the fault, the velocity structure, and noise. Also, the influence of the sampling rate, the time window of the data and the distribution of observational stations is studied. Our research indicates: The near-source waveform data can adequately recover the source rupture process of the shallow part of the fault. However, they poorly constrain the slip distribution on the deep part of the fault. Using near-source and teleseismic waveform data jointly can provide a more complete view of the rupture process of the whole fault. The result using near-fault data is very sensitive to the assumed strike and dip parameters of the fault model. A 2° deviation of the presumed strike and a 5° deviation of the presumed dip from that of the true fault will lead to a distorted inversion result. The influence of the uncertainty of the seismic velocity structure for the Chi-Chi earthquake might be ignored if we can take the difference between Ma et al.'s model and Wu et al.'s model as the measure of the media uncertainty.

QUANTUM COHERENCE IN NEUTRON SCATTERING ON PROTONS

Several recent observations of closely spaced hydrogen nuclei in condensed matter systems — water, polymers and metal hydrides — indicate that they cannot be considered as independent quantum objects when observed over very short time intervals. According to these measurements, pairs (or possibly small clusters) of protons or deuterons seem to be quantum correlated, and are able to preserve their mutual quantum phase relations over times of the order of femtoseconds even in strongly perturbing liquid or solid environments. These new experimental results are mainly based on scattering of neutrons with time windows in the atto- and femtosecond range, but there also exists corroborating evidence from other spectroscopies. When the width of the observational time window is increased above a characteristic value, the quantum coherence effects are seen to disappear. This time limit marks the onset of decoherence as the mutual phase relations between the particles are gradually lost. Possible reasons for short-time entanglement of nuclei in condensed matter systems, as well as mechanisms for its decoherence will be discussed.

Selection of Time Window Width and its Effects on the Numerical Simulations of Optical Pulse Propagation in Fibers

In order to ensure the accuracy of the split-step Fourier method used to study numerically the optical pulse evaluation in fibers, the selective problem of time window width is focused on in this paper. After giving the selective method of the time window width and the minimum time window width required for corrected calculations of optical pulse propagation in fibers, the shapes of various incident pulses after passing through different fiber lengths have been simulated by selecting different time window widths. The viewpoint that a super-Gaussian pulse distorts in shape on propagation, which was reported by other researchers, has proved to be mistaken.

5380504 Treatment of gold bearing ore

In today’s competitive environment, one of the most critical objectives for Home Health Care (HHC) companies is to meet the demand of patients in a timely fashion. According to the feedback from HHC companies, caregivers have to deal with some uncertainties when carrying out a given schedule to visit their patients. However, a majority of the previous work only considers the deterministic models which ignore the uncertainties, and solutions obtained by these deterministic models are usually less robust in case of any possible changes in practical situations. Inspired by this point, in this work, we formulate a model for an HHC Routing and Scheduling Problem with taking into account uncertain travel and service times, from the perspective of Robust Optimization (RO). Specifically, the non-deterministic variables are defined based on the theory of budget uncertainty, and then the arrival time of each caregiver is rewritten as a complicated recursive function. After that, Gurobi Solver, Simulated Annealing, Tabu Search, and Variable Neighborhood Search are adapted to solve the model respectively. Finally, a series of experiments have been performed to validate the proposed models and algorithms. Experimental results from Monte Carlo simulation highlight the strength of considering uncertainties when modeling the problem. Additional, the influences of other characters in instances, like the width of time-window, distributed location have also been empirically analyzed. Finally, the comparison performed between the solutions obtained by the stochastic model and the RO model also demonstrates the advantage of the RO model. This work provides a valuable framework for HHC companies to make a robust schedule when arranging the caregivers.

Effect of pH and sodium dodecyl sulfate concentration on the analytical window in the direct‐injection analysis of plasma samples by capillary electrophoresis

Plasma samples can be analyzed with direct injection onto a capillary electrophoresis system if interactions between the plasma proteins and capillary walls are minimized. This can be achieved using micellar electrokinetic capillary chromatography with a surfactant such as sodium dodecyl sulfate. The surfactant complexes with the proteins, giving them a net negative charge, and thus causes them to be repelled from the negatively-charged fused-silica capillary walls. Migrating as anions, the complexed proteins appear late in the electropherogram. In such analyses, it is important to manipulate the mobility of the analyte(s) of interest such that they migrate in the useful analytical time window before the plasma proteins. In this article, a study of the effect of buffer pH and surfactant concentration on the width of the migration time window is reported. It is shown that at pH 6 the migration time window is wide, but reduced electroosmosis can result in inordinately long run times; pH 7 gives an acceptable analytical window with acceptable run times over a wide range of sodium dodecyl sulfate (SDS) concentrations; pH 8 and higher are most useful when higher concentrations of surfactant (> 50 mM SDS) are employed.

Micellar electrokinetic capillary chromatography with in situ charged micelles: IV. Influence of the nature of the alkylglycoside surfactant

Four different in situ charged micellar phases were evaluated in micellar electrokinetic capillary chromatography (MECC) of neutral and acidic herbicides, and other aromatic compounds. In situ charged micelles refer to dynamically charged entities that are formed via the complexation of borate with surfactants having sugar head groups. These dynamically charged surfactants yield micelles with adjustable surface charge densities which can be conveniently manipulated by changing borate concentration and pH of the running electrolyte. The four surfactants, namely octanoylsucrose (OS), octyl-β- d-glucopyranoside (OG), octyl-β- d-maltopyranoside (OM) and nonanoyl- N-methylglucamide (MEGA 9), in the presence of alkaline borate yielded micelles characterized by migration time windows of varying width. The width of the migration time window was largely influenced by the nature of the sugar head group of the polyolic surfactant. The electrochromatographic behavior of OS, OM, OG and MEGA 9 was influenced by both the nature of the sugar head group and the length of the alkyl tail. OS, which differed from the other surfactants by having an alkyl tail with one fewer carbon atom, exhibited the lowest retention. MEGA 9 with its acyclic sugar head group and the presence of a polar amide linkage between the sugar and the alkyl tail showed a medium retentivity towards the various solutes under investigation. OG and OM, which differed from each other by the nature of the sugar head group, exhibited more or less similar retention behavior. Overall, due to differences in their migration time windows and retention behaviors, the four micellar phases afforded different selectivities toward charged and neutral solutes. The separation efficiencies achieved with in situ charged micelles, which exceeded 750 000 plates/m, appear to be superior to those achieved with traditionally used micellar phases.

Backscattered echoes from submerged elastic shells insonified by short realistic pulses using Wigner-type distributions

Significant features in the backscattered echoes of shells insonified by idealized pulses were studied earlier [J. Acoust. Soc. Am. 91, 2384 (A) (1992)], in the frequency, the time, and particularly in the combined time–frequency (t–f) domain. In this last case, (Gaussian) time-windowed Fourier transforms (TWFT) and pseudo-Wigner distributions (PWD) of the returned pulses were used. This analysis is now extended here to finite, realistic, incident pulses, with either rectangular or sinusoidal envelopes. The above distributions extract from the returned pulses the time-evolution of the resonances the target may have in the chosen (broad) band of operation. This band includes the so-called medium-frequency range. The selection of suitable carrier frequencies produces t–f-domain displays with recognizable features linked to specific target characteristics. One of these is, for example, the mid-frequency enhancement ‘‘hump,’’ present at ‘‘coincidence,’’ which determines the shell thickness. Adjusting the time-window widths controls the amount of detail in the displays, which will be shown in an informative colorized format in 3-D.

Time-Domain Measurements of Microwave Components

Recent advances in microwave component measurements using time-domain techniques are described. After reviewing the basic elements of a time-domain system, a substitution procedure is applied to determine the insertion loss of wide-band attenuators. Comparison of these measurements with frequency calibrations shows agreement to within 0.1 dB in 10 dB for attenuators between 10-50 dB, over the frequency range 0.4-8 GHz. Error sources are resolved by experiments designed to isolate and evaluate various contributions including: random errors due to noise and drifts; systematic errors caused by substitution attenuator inaccuracies, line mismatch, deflection nonlinearities, and inaccurate time window widths; time-to-frequency translation errors of aliasing and truncation; and mechanical errors due to connect-disconnect cycles. Results show that random processes are responsible for most of the observed error. The reported measurements establish the calibration capabilities and the expected magnitude of individual system errors for the particular system tested.