For nearly 80·years, the non-iridescent, blue, integumentary structural colours of dragonflies and damselflies (Odonata) have been attributed to incoherent Tyndall or Rayleigh scattering. We investigated the production of the integumentary structural colours of a damselfly – the familiar bluet, Enallagma civile (Coenagrionidae) – and a dragonfly – the common green darner, Anax junius (Aeshnidae) – using fibre optic spectrophotometry and transmission electron microscopy (TEM). The reflectance spectra of both species showed discrete reflectance peaks of ~30% reflectance at 475 and 460·nm, respectively. These structural colours are produced by light scattering from closely packed arrays of spheres in the endoplasmic reticulum of box-shaped epidermal pigment cells underlying the cuticle. The observed reflectance spectra do not conform to the inverse fourth power relationship predicted for Tyndall/Rayleigh scattering. Two-dimensional (2-D) Fourier analysis of the TEM images of the colour-producing arrays reveals ring- shaped distributions of Fourierpower at intermediate spatial frequencies, documenting a quasiordered nanostructure. The nanostructured Fourierpowerspectra
These results provide an important insight into how diversity in nanostructure and optical function may have evolved in lepidopterans through selection on novelties in optical function. For example, the Fourierpowerspectra (Fig.·6B) of the intersections of the concave multilayers of air bubbles in Papilio ulysses (Fig.·4E) demonstrate how internal laminar (Type II) and internal crystal-like (Type IIIa) nanostructures can intergrade into one another. These scale concavities function and have likely evolved by selection to reduce iridescence (see above, Fig.·10), and have produced the periodic establishment across the scale of an intermediate form of nanostructure between laminar and crystal-like arrays (Figs·4E, 6B). It is easy to imagine how selection on optical function could lead to an evolutionary transition between these two types of nanostructures. Furthermore, the deeper concavities of Papilio palinurus that produce optical colour- mixing of yellow and blue (Vukusic et al., 2000b; Vukusic et al., 2001a) likely evolved as derived elaborations of the type of iridescence reducing concavities found in Papilio ulysses.
Figure 5 shows the Fourier and modified Fourierpower spec- tra, and we find a significant peak at about 12 yr period in a test against red noise. This peak is not significant in tradi- tional tests. The main reason for the increased significance is the removal of boundary effect in our new significance test. Notice also that the modified Fourierpowerspectra has higher resolution than traditional spectrum due to the odd ex- tension made to the original time series. This high resolution may result in sharper spectral peaks at any period which is especially noticeable around 12 yr in Fig. 5.
propagation of the ion saturation current fluctuations is ob- served with every other tip of the 64-channel probe array. We define the positive direction for the azimuthal angle θ as the direction of electron diamagnetic drift. Windowed Fourier Transform (FT) is performed for both time and azimuthal space to calculate the two-dimensional power spectral density as a function of frequency f and az- imuthal mode number m, where the sign of the mode num- ber gives the propagation direction. A time window of ΔT = 3 ms is used to obtain a frequency resolution of Δf = 0.3 kHz. Figures 5 (a) and (b) are conditional aver- aged power spectral density for the lower and upper states. In the lower state, the dominant fluctuating mode is located at (m, f ) = (2, 6.7 kHz). In addition, a counter-propagating mode at (m, f ) = (−1, 1.3 kHz) is excited. In the upper state, the counter-propagating mode is still observed but its frequency slightly changes to f = 1.0 kHz. The mode number and frequency of the dominant mode are changed to (m, f ) = (1, 2.3 kHz). The broad spectra can have many combinations of three-wave coupling. In particular, three- wave couplings involving the counter-propagating mode have been considered playing an important role for the nonlinear excitation process of the streamer structure in the LMD-U . We discuss similarities between the spectra for the two states and the spectra obtained for discharges with slightly decreased and increased neutral gas pressure. In both neighboring neutral gas pressure conditions, no transitions are observed, and fluctuation spectra remain un- changed during the whole discharged. Fluctuation spectra for the cases of P n = 0.13 Pa and P n = 0.17 Pa are drawn
In Figure 4 we provide a sneak peek at a power spec- trum of a low-luminosity red-giant star as it would be observed by TESS at the 30-min cadence. The two pan- els in this figure show the powerspectra of Kepler-56 as observed both by Kepler (in its long-cadence mode) and TESS based on 1 year of observations. As can be seen, oscillations are easily identified in either power spectrum. Notice, however, that while the granulation power and shot noise levels are commensurate for the Kepler power spec- trum, the shot noise level is one order of magnitude higher than the granulation power in the case of the TESS power spectrum. This is mostly due to the smaller (by 2 orders of magnitude) effective collecting area of the individual TESS cameras.
In this paper, we propose and justify a method for estimating the amplitude-frequency characteristics (AFC) of the retina by processing the signals of the flicker ERG (FERG) and ERG responses to the chess pattern - black-and-white reversal cells (PERG). It is shown that the frequency response is an objective characteristic of the transfer properties of the retina, which depend not only on the type of stimuli acting on it but also on the etiology of retinal pathology. The purpose of the research is to search for additional formalized (digital) signs of retinal pathologies by analyzing the frequency response to expand the attribute space for diagnosis. The photopic FERG and transient PERG responses were recorded in six healthy individuals and six patients with stage I and stage II primary open-angle glaucoma (POAG). The digitized FERG and PERG signals were decomposed into a Fourier series and, taking into account the spectra of test stimuli, the retinal frequency response of different individuals was constructed, and their properties were studied as a dynamic object transforming the spectrum of the test stimulus into the spectrum of the recorded ERG. We proposed to use the coefficients of polynomials smoothing the resulting frequency response as new formalized diagnostic features. Each frequency response is submitted to be divided into two frequency ranges, and each of them uses its own algebraic smoothing polynomial. We used the results of modeling in Matlab Simulink to identify the characteristics of retinal responses to the flicker- and pattern-stimulation.
Samples were prepared for infrared spectroscopic measurements by taking about 1 mg of the human IgG which has been prepared in the Biotechnology laboratory of our college and 100 - 150 mg of KBr grinded to- gether, finally dried to remove moisture and pressed at elevated temperature under high pressure into a small disc. A clear pellet is obtained. The infrared spectra of prepared samples were recorded in the range from 400 cm –1 to 4000 cm –1 with single beam Fourier transform infrared spectrophotometer, Perkin Elemer Model-1710. This instrument has the following units and features. IR source which had temperature established ceramic source operating at 1400 K. The abscissa accuracy and ordinate precision are 0.01 cm –1 and 0.1% T, respectively. This instrument has a resolution of 1 cm –1 to 64 cm –1 [1 cm –1 with a memory option fitted]. The ambient tem- perature and relative humidity are 15 ° C to 35 ° C and 75% max, respectively. There are three units, which are given here: 1) centre processing unit 2) cathode ray tube and 3) fast recovery deuterated triglyceride sulphate detector.
Fourier transform infrared spectroscopy (FTIR) is a technique which is used to obtain an infrared spectrum of absorption, emission, photoconductivity or Ramanscattering of solid, liquid or gas. An FTIR spectrometer simultaneously collects spectral data in a wide spectral range. An FT-IR Spectrometer is an instrument which acquires broadband NIR to FIR spectra. Unlike a dispersive instrument, i.e. grating monochromator or spectrograph, FT-IR Spectrometers collect all wavelengths simultaneously. FT-IR (Fourier Transform Infra Red) is a method of obtaining infrared spectra by first collecting an interferogram of a sample signal using an interferometer, and then performing a Fourier Transform (FT) on the interferogram to obtain the spectrum. The main goal of FTIR spectroscopic analysis is to determine the chemical functional groups in the sample. Using various sampling accessories, FTIR spectrometers can accept a wide range of sample types such as gases, liquids, and solids. Thus, FTIR spectroscopy is an important and popular tool for structural elucidation and compound identification.
fourier transform Infra red spectra, powder X-ray diffraction, High resolution scanning electron microscopic analysis, Transmission electron microscopic analysis, Thermal analysis, and Elemental analysis. The process presented here is operationally simple, environmentally benign and affords excellent yields without the need for any solvent.
Recent seismological observations focusing on the collapse of an impulsive wavelet revealed the existence of small-scale random heterogeneities in the earth medium. The RTT has often been used for the study of the propagation of wavelet intensities, the MS amplitude envelopes. For the statistical characterization of the PSDF of random velocity inhomo- geneities in a 3-D space, we have used von Kármán type functions with three parameters: the RMS fractional veloc- ity fluctuation ε, the characteristic length a, and the order κ of the modified Bessel function of the second kind. This model leads to the power-law decay of PSDF ∝ m −2κ−3 at wavenumber m higher than the corner at a −1 . We have com- piled reported statistical parameters of the lithosphere and the mantle based on various types of measurements for a wide range of wavenumbers: photo-scan data of rock samples, acoustic well-log data, and envelope analyses of cross-hole experiment seismograms, regional seismograms, and tele- seismic waves based on the RTT. Reported κ values are dis- tributed between 0 and 0.5 (PSDF ∝ m −3 to −4 ), where many of them are close to 0 (PSDF ∝ m −3 ). Reported ε values are on the order of 0.01–0.1 in the crust and the upper mantle, where smaller values in the lower mantle and higher values beneath volcanoes. Reported a values distribute very widely; however, each one seems to be restricted by the dimension of the measurement system or the sample length. In order to grasp the spectral characteristics, eliminating strong hetero- geneity data and the lower mantle data, we have plotted all
ABSTRACT: This study aims to compare the Parkinsonism behavior induced by two drugs: Tacrine (9-amino-1,2,3,4-tetrahydroaminoacridine hydrochloride hydrate and MPTP (1-methyl, 4-phenyl 1,2,3,6 tetrahydropyrolidine) using a Force Plate Actimeter (FPA). 25 C57BL/6 black mice were equally divided into two groups for 5mg/kg tacrine and 30mg/kg MPTP experiment. Both groups contained sham, 5mg/kg tacrine or 30mg/kg MPTP group and sinemet group (oral administration of 10mg/kg sinemet (levodopa:carbidopa in 4:1) prior to intraperitoneal injection of 5mg/kg tacrine or 30mg/kg MPTP). Mice were immediately kept inside FPA to record their behavior. Distance travelled, bout of low mobility (BLM) and powerspectra of parkinsonian symptoms shown by both drugs were computed. Both neurotoxins reduced the motor abilities of mice in comparison with sham. Oral treatment of sinemet improved their disability. According to powerspectra analysis, tacrine had only one significant narrow peak from 10-12 Hz while MPTP exhibited one to four peaks from 8 to 12 Hz. This might be because the behavior expected from tacrine is lateral movement of jaw (facial part) whilst that of MPTP is rigidity and tremor (facial, trunk and tail portion). This experiment indicates that both tacrine and MPTP can possibly impair motor functions of C57BL/6 black mice. It is possible to use these results to create Parkinsonism model in laboratory by the use of FPA. This model may be used to evaluate capability of new anti parkinsonian drugs to improve motor abilities in rodents.
In this work, the fabric variability in layers of a 2/2 twill weave were determined by automated analysis of optical images taken during the lay-up process on the component scale. There is no need for transmissive light to determine bundle spacing, which necessitates a trans- parent mould tool and is only applicable for the study of a single textile layer. 22 The proposed analysis of yarn edge detection is limited to sample surfaces only; however, the limited thickness of the yarns allows out-of-plane paths to be estimated. The implemented image analysis process enabled intrinsic misalignment such as varying in-plane waviness and handling induced shearing, both of which aﬀect the ﬁbre angle, to be quantiﬁed. Tedious and time consuming manual determination of bundle edges 23,24 is overcome. Automatically analysing edges of visible, small bundle segments in this work allows in-plane bundle waviness and small local width changes to be determined. Methods which ﬁt higher order polynomials to the determined edges of longer bundle lengths 25,26 may not capture these small changes. The implemented ana- lysis method of the spatial domain provides detailed information on local yarn path orientations and yarn width changes which cannot be determined when ana- lysing images in the frequency domain, e.g. Fourier analysis of larger images of textile reinforcements. 27
Abstract. We propose a new generative model for polyphonic music based on nonlinear Independent Subspace Analysis (ISA) and factorial Hidden Markov Models (HMM). ISA represents chord spectra as sums of note powerspectra and note spectra as sums of instrument-dependent log-powerspectra. HMM models note duration. Instrument-dependent parameters are learnt on solo excerpts and used to transcribe musical recordings as collections of notes with time-varying power and other descriptive parameters such as vibrato . We prove the relevance of our modeling assumptions by comparing them with true data distributions and by giving satisfying transcriptions of two duo recordings.
a) Write a MATLAB script to determine the complex Fourier series for a square-wave periodic signal with a fundamental period of 1 kHz, a 75% duty cycle, with an amplitude of 1 volt peak-to-peak. b) Use the subplot command to create a figure with a top and bottom panel. In the top panel, plot the original signal and your Fourier series approximation with 10 harmonics. In the bottom panel, plot the single-sided power spectrum of the input signal in dBmV for the first 10 harmonics. Turn in your plot. Have your program print out the values of the spectral components and fill in the Predicted Values in Table 3 on the worksheet at the end of this lab.
The most common electron beam lithography systems are based on standard scanning electron microscopes. However, the quest for high throughput has lead to the development of expensive and complex dedicated lithography systems, the price of which can exceed the range of 3M GBP. In brief, the technique consists of scanning a beam of electrons across the surface of a sample covered with a resist film sensitive to the electrons’ radiation. In this way, the beam deposits energy on certain areas of the resist and thus a pattern is defined on its surface. The core of the system is the column that consists of an electron source and the control elements for the electron beam (lenses, stigmators, blankers, detectors etc.). Underneath the column, the sample is mounted on a translation stage, the position of which is controlled by a laser interferometer. Both the sample and the column operate under ultra-high vacuum. A complex set of electronics, which supplies the signal and power to the various components, completes the system. The complexity of the electron beam lithography stems from the electron-solid interactions involved during the exposure. Upon penetrating the resist, electrons experience several small-angle scattering events that tend to decrease the resolution of the exposure. These manifest themselves via the broadening of the incident electron beam diameter and is refered to as forward scattering . Subsequent to the resist, the electrons penetrate the substrate and undergo large-angle scattering events (backscattering). This affects the size of an exposed feature, since the dose it receives is increased due to backscattered electrons from a nearby feature. The latter is the proximity effect and the simplest way to control against it is to modulate the dose during the exposure and in accordance to the shape- shape interactions that are involved.
A strong variation with a period of 8900 - 10,040 years is a shared feature in all analyzed time series (Figure 6 and Figure 7). This is also evident in Figure 3. We call this variation a quasi 10 kA periodicity. This periodic- ity results in correlation between higher-frequency parts of the paleorecords—see Table 1. The significance of correlations P corr was estimated statistically including permutation of phases of Fourier transform. In all cases
To demonstrate the effectiveness of the proposed approach an elastic displacement response spectrum defined by the European Standards (CEN, 2003), pertaining to a specific ground type and design ground acceleration is selected as the target design spectrum. The requisite parameters for the complete analytical definition of two different forms of exponentially modulated powerspectra are determined. The forms examined are the Kanai-Tajimi (Kanai, 1957), and the Clough-Penzien (Clough and Penzien, 1993), power spectrum. Ensembles of synthetic time histories compatible with the considered evolutionary powerspectra are generated and their average response spectra are compared to the target spectrum to assess the potential of the corresponding spectral forms to yield an acceptable level of matching. Furthermore, the effectiveness of the harmonic wavelet transform for properly modifying a single accelerogram, arbitrarily selected out of the generated ensembles, so that its displacement response spectrum to be in a very close agreement to the target spectrum is illustrated. Note that the fact that artificial accelerograms require certain baseline corrections to yield realistic displacement time histories is taken into account and is properly addressed in the case of the above modified single accelerogram.