Variation Of Peak Height Research Articles

Barkhausen noise in ferromagnetic metallic glass Fe40Ni38Mo4B18

The influence of heat treatment on conventional magnetic properties and Barkhausen noise were studied in ferromagnetic amorphous Fe40Ni38Mo4B18 during a half magnetization cycle for both amorphous and crystallized states. The coercivity, Hc, was low in the amorphous specimens and maximum as the crystallization starts, and decreased with further annealing. The differential permeability near to the Hc, μc, was high in the amorphous specimens and minimum at the onset of crystallization, then increased with annealing. The single peak behavior of the Barkhausen noise (BN) envelope was a common feature in both amorphous and crystallized specimens, and the variation of peak height with heat treatment was similar to that of μc. The magnetic anisotropy energy constant, Ku, was lowest when the crystallite started to nucleate in the amorphous specimen, and increased as the crystallite size grows. The difference between ribbon and transverse directions of BN characteristics such as BN energy, peak height of BN envelope, Hp, and corresponding field strength to Hp, respectively, was the lowest at the onset of crystallization, and increased with Ku. A model was proposed to predict the linear relationship between the magnetic anisotropy energy constant detected by torque measurement and the one evaluated by BN measurement.

The perceptual salience of melodic variation: contour shape and peak height

This paper describes an experiment that was run in order to determine the relative salience of two kinds of melodic variation: variation in the shape of contours belonging to the same intonation pattern or in the height of accent-lending pitch peaks. The outcome suggests that variation of contour shape is perceptually more salient than variation of peak height. In addition, it was noticed that variation of peak height in the first pitch movement is more conspicuous than that in the second. Finally, it is observed that diverging toplines are perceptually more salient as different from toplines that parallel the baseline than converging ones.

A METHOD TO MEASURE SULFUR-CONTAINING VOLATILES IN ONIONS USING A GAS CHROMATOGRAPH.

A 50 g sample taken as a horizontal section from the mid-height of an onion bulb was blended with 100 g water for 1 min in a closed plastic mason jar. A 0.5 ml of a headspace sample was drawn and injected into a Perkin Elmer 8500 GC equipped with FPD for detection of sulfur compounds. The major volatiles tentatively identified in onion were thiopropanal S-oxide, methyl propyl disulfide, dipropyl disulfide, and propyl allyl disulfide. We observed significant variation of peak pattern and height depending on position in a bulb, among bulbs within variety, and between varieties. These results seemed to comply well with taste test. There were no significant correlations between total peak height and bulb weight, soluble solids, or pyruvate concentration in juice extract. Our investigation suggested that this procedure provided better understanding and measurement of onion pungency than pyruvate analysis.

Effect of sulphur on the hydrogen trapping phenomena at the grain boundary in iron

The hydrogen trapping phenomena at grain boundaries in the iron-sulphur system were investigated by the hydrogen thermal analysis technique. The specimens were heat treated to produce the same grain size, and the concentration of sulphur at the grain boundaries was controlled by isochronal treatment at various temperatures. The peak height related to the hydrogen released from the grain boundaries decreased with increasing sulphur content at the grain boundaries. It is suggested that the variations in peak height may be attributed to the lowering of the trap binding energy due to sulphur segregation and the site competition effect between the segregated sulphur and hydrogen which are trapped at the grain boundaries.

Optical-emission-spectroscopic studies of the sputtering of Y-Ba-Cu-oxide thin films

Optical emission spectroscopy is used to determine the identity of species ejected during sputtering of a composite Y-Ba-Cu-oxide target. In this experiment, Y, Ba, Cu, Ba+, and YO were detected near the surface of the target, indicating that oxygen is transported to the substrate during sputtering. Varying of the sputter ion energy caused some variation in relative peak heights, but changing the gas mixture in the system did not significantly alter the spectra.

Spectral Searching by Fourier-Phase Correlation

A new idea of spectral library searching is proposed, in which only the phase components of Fourier transforms of both the sample and the reference spectra are used for spectral identification. Compared with the conventional methods, this method has essentially a very high discrimination ability for distinguishing between similar spectra and is very resistant to the peak-height variation and the peak-position shift due to the experimental conditions. The principle and the algorithm of this library search method are described, along with the experimental results for infrared absorption spectra. The results demonstrate that the proposed method gives much lower scores for wrong reference spectra than does the ordinary correlation method, and gives high scores for the sample spectra measured by the various slit widths of the spectrophotometer.

Near-edge x-ray-absorption fine structure in uranium compounds.

For a number of metallic and nonmetallic U systems as well as a few Th compounds, the near-edge x-ray-absorption fine-structure spectra, taken by transmission and total-electron-yield techniques, are reported at the ${L}_{3}$, ${M}_{3}$, ${M}_{4}$,5, ${N}_{4}$,5, and ${O}_{4}$,5, thresholds. At ${L}_{3}$ and ${M}_{3}$, similar spectra with analogous information are observed. While in the metallic U systems, the white lines at ${L}_{3}$ and ${M}_{3}$ show only minor variations in position and relative peak height, a shift of \ensuremath{\simeq}4 eV is observed between ${\mathrm{UCl}}_{3}$ and ${\mathrm{UF}}_{4}$, representing mainly the difference in Coulomb interaction between a 2${p}_{3/2}$ core hole and the 5f configurations. The spectra at the ${M}_{4}$,5 and ${N}_{4}$,5 thresholds are dominated by intense absorption peaks due to 3d-5f and 4d-5f transitions probing directly the unoccupied 5f states. No multiplet structure due to 3d-5f or 4d-5f exchange interaction is resolved, but the linewidths of the ${M}_{4}$,5 peaks in the metallic U systems are found to decrease by \ensuremath{\simeq}20% with increasing U-U distance, reflecting a narrowing of the unoccupied 5f bands. The spectra at the ${O}_{4}$,5 thresholds, on the other hand, show well-resolved structures, which are atomiclike for ${\mathrm{ThF}}_{4}$ and ${\mathrm{UF}}_{4}$ and may be described by spin-orbit and exchange splitting of the 5${d}^{9}$5${f}^{1}$ and 5${d}^{9}$5${f}^{3}$ final states, respectively. In metallic U systems, the ${O}_{4}$,5 structures are broadened and partly lost, presumably due to the more itinerant nature of the 5f states. Additional relatively weak peaks are observed in the ${M}_{4}$,5 and ${O}_{4}$,5 spectra of Th metal, ${\mathrm{ThO}}_{2}$, ${\mathrm{UO}}_{2}$, and ${\mathrm{UF}}_{4}$ at energies from \ensuremath{\simeq}15 to 38 eV above threshold, which are assigned to multiple-scattering resonances.

Electrochemical behaviour of pure iron in concentrated sodium hydroxide solutions at different temperatures: a triangular potential sweep voltammetric study

The passivation and dissolution of pure iron in NaOH solutions (1 M–10M) have been studied at 30°, 60° and 80° C by triangular potential sweep voltammetry. The variation of peak height and peak potential with sweep rates for the three anodic peaks in the forward direction and two cathodic peaks in the backward direction when polarized from −1.30 V in 1.0 M NaOH solution, suggest that a monolayer adsorption model holds good. The appearance of limiting currents at higher concentrations of NaOH has been explained in terms of the chemical dissolution of two oxides formed by successive oxidation. The formation of different oxides, hydroxides and solution soluble species under transient conditions has been discussed.

Study of peak profiles in nonlinear gas chromatography: Application to the peak distortions observed with overloaded capillary columns

AbstractThe elution profiles observed with overloaded capillary columns are well described by a four‐parameter theoretical model derived from the basic mass balance equations which relies on an expansion of the partition isotherm to the second term and takes the sorption effect into account. The reliability of the model is demonstrated by the fact that the peak leaning coefficient obtained from a least squares fit of the model to the experimental peak is in good agreement with that obtained from the variation of peak height with retention time at peak maximum. The coefficeint of apparent axial dispersion is independent of sample size and can be used to characterize the plate height at zero concentration of an overloaded capillary column.

Quantitative AES analysis of Fe-Cr and Fe-Ni-Cr alloys

Conventional, derivative mode AES, in combination with Ar + sputtering, was applied to a wide range of commercial Fe-Cr and Fe-Ni-Cr alloys. The roles played by matrix effects, sputtering phenomena, peak interference, peak height variation and poor vacuum backpressure in obtaining quantitative analyses were studied. Alloys were analysed in both oxidised and sputter-cleaned states, with several techniques being developed to allow rapid and simple quantitative analysis.

Model for the adsorption of cytochrome c at the water-mercury interface.

AbstractThe effect of cytochrome c on the redox behavior of 1,4‐benzoquinone and cystine has been investigated by differential pulse polarography. The adsorption of cytochrome c on mercury surface produces a lowering of the reduction peak of 1,4‐benzoquinone and of the cystine prepeak. When the covering of the drop is maximal, no variation in peak height is observed. By using the Koryta equation, values between 1500 and 2300 Å2 for the surface area of one adsorbed cytochrome c molecule were obtained. The capacitance dependences on concentration and time have been determined by alternating‐current polarography, and lead to the surface area values of 2800 and 2700 Å2, respectively. Results are interpreted on the basis of an unfolding of cytochrome c molecules during the adsorption process. It is likely that a rather compact covering is obtained, but about 10% of the mercury surface seems to be unoccupied and corresponds to the accessible interstices between adjacent molecules.

Temperature dependence of peak heights in deep-level transient spectroscopy

With the aid of a high precision computer simulation we demonstrate that the frequently observed variation in DLTS peak height with emission rate window is not necessarily caused by nonexponential capacitance transients as is often supposed, but rather by the change in shape of the Debye tail with temperature. This variation in peak height is shown to be a function of temperature, reverse bias and trap depth.

Observations and models of inertial waves in the deep ocean

The structure of the inertial peak in deep ocean kinetic energy spectra is studied here. Records were obtained from Polymode arrays deployed in the Western North Atlantic Ocean (40°W to 70°W, 15°N to 42°N). The results are interpreted both in terms of local sources and of turning point effects on internal waves generated at lower latitudes. In most of the data, there is a prominent inertial peak slightly above f; however, the peak height above the background continuum varies with depth and geographical environment. Three classes of environment and their corresponding spectra emerge from peak height variations: class 1 is the 1500‐m level near the Mid‐Atlantic Ridge, with the greatest peak height of 18 dB; class 2 includes (a) the upper ocean (depth less than 2000 m), (b) the deep ocean (depth greater than 2000 m) over rough topography, and (c) the deep ocean underneath the Gulf Stream, with intermediate peak height of 11.5 dB; class 3 is the deep ocean over smooth topography, with the lowest peak height of 7.5 dB. Near f, the horizontal coherence scale is 0 (60 km) at depths from 200 m to 600 m, and the vertical coherence scale is 0 (200 m) in the lower part of the main thermocline and 0 (1000 m) in the deep water; the phase difference suggests a downward energy propagation in the lower thermocline and standing waves in the deep water. A one‐turning‐point model is developed to describe inertial waves at mid‐latitudes, based on the assumption that inertial waves are randomly generated at lower latitudes (global generation) where their frequency‐wave number spectrum is given by the model of Garrett and Munk (1972, 1975). Using the globally valid wave functions obtained by Munk and Phillips (1968), various frequency spectra near f are calculated numerically. The model yields a prominent inertial peak of 7 dB in the horizontal velocity spectrum but no peaks in the temperature spectrum. The model is latitudinally dependent: the frequency shift and bandwidth of the inertial peak decrease with latitude; energy level near f is minimum at about 30° and higher at low and high latitudes. The observations of class 3 can be well described by the model; a low zonal wave number cutoff is required to produce the observed frequency shift of the inertial peak. The differences between the global generation model and the observations of class 1 and class 2 are interpreted as the effects of local sources. A locally forced model is developed based on the latitudinal modal decomposition of a localized source function. Asymptotic eigensolutions of Laplace’s tidal equation are therefore derived and used as a set of expansion functions. The forcing is through a vertical velocity field specified at the top or bottom boundaries of the ocean. For white noise forcing, the horizontal velocity spectrum of the response has an inertial peak which diminishes in the far field. With the forcing located at either the surface or the bottom, several properties of the class 2 observations can be described qualitatively by a combination of the global and local models. The reflection of inertial waves from a turbulent benthic boundary layer is studied by a slab model of given depth. Frictional effects are confined to the boundary layer and modeled by a quadratic drag law. For given incident waves, reflection coefficients are found to be greater than 0.9 for the long waves which contain most of the energy. This result suggests that energy‐containing inertial waves can propagate over great distance as is required by the validity of the model of global generation.

Determination of Penicillinase-Resistant Penicillins In Serum Using High-Pressure Liquid Chromatography

Abstract A method for the determination of methicillin, oxacillin, cloxacillin, dicloxacillin, and nafcillin in serum using high-pressure liquid chromatography (HPLC) is described. The drugs were extracted from serum using a two-step procedure employing acetonitrile followed by methylene chloride. The extraction procedure concentrated the antibiotics in a smaller volume which allows more accurate determinations of low serum levels. The treated sera were analyzed by HPLC on a reverse-phase column and detected by ultraviolet light absorption at 254 nm. Serum concentrations were measurable as low as 0.5 μg/ml. Recovery procedures showed less than 2.5% variation in peak heights when the antibiotics were extracted from different pools of serum. No interfering absorption was found in extracts of serum samples pooled from healthy volunteers, from a commercial source, or from two serum pools from patients receiving a variety of other drugs. Two spiked serum specimens prepared for each antibiotic were assayed four times by HPLC and by the microbiological agar diffusion method. No significant statistical differences between the methods were observed. Control materials were assayed for between-batch and within-batch reproducibility in the presence or absence of an internal standard. Results for between-batch reproducibility demonstrate CV's of about 5%. This procedure provides a sensitive, specific, accurate, and rapid method for determining antibiotic levels in routine clinical specimens.

Onset of puberty in MX and DZ twins.

A twin study on the significance of genetic factors for the variation in peak height and peak weight velocity, as well as in age at menarche and the development of secondary sex characteristics, is presented. Evidence of a rather strong genetic regulation of the occurrence of puberty was obtained in the analysis. The maximal height or weight gain (in cm/year of kg/year) seems to be, at least in girls, less influenced by genetic factors than the age at which it appears.

Effect of quenching on Snoek curves of commercial sheet steels

Abstract Using a low-frequency torsional pendulum, the effects of quenching temperature on the Snoek curves of a vacuum-melted electrolytic iron, a rimmed steel, and an Alkilled sheet steel were investigated. It has been observed that the Snoek peak height and peak breadth of the above materials are changed not only by specimen dimensions but also by the quenching temperatures. Marked variations in peak height have been observed and are associated with the dissolution of carbides and nitrides in a-iron and an effect due to the γ-α transformation. The quenching from the γ-region causes broadening of the Snoek peak. A relationship between total nitrogen content and damping capacity Q -l max . has been derived and is discussed for commercial materials.

Effect of Halide Ions on the Adsorption Prewave of Methylene Blue

In the present study, the familiar Langmuir adsorption isotherm is applied to the mixed adsorption of methylene blue in the presence of halide ion. The variation of methylene blue prewave height or AC peak height with halide ion concentration is treated statistically. It is concluded that the decrease in the DC prewave or in the corresponding AC peak height is caused by the mixed adsorption of halide ion. The relative temperature coefficient of AC perk height was found to be 1.04% deg-1 at 25°C in 0.4M KNO3 with acetate buffer solution (pH 4.7).

Conductance Peaks in a Cylindrical Plasma Capacitor at the Cyclotron Harmonics

Theoretical and experimental results are presented for the conductance peaks at the cyclotron harmonics in a plasma-filled cylindrical capacitor. A theory is developed and is shown to predict peak height variation with density, harmonic number, and sheath thickness that is in agreement with experimental observation. A harmonic conductance peak is found to rise initially as density increases, only to fall to a minimum height as the upper hybrid frequency passes through that harmonic. Possible applications of this work to plasma diagnostics and further research are mentioned.

Electroabsorption of CdS and CdSe Single Crystals in the Exciton Region

AbstractElectroabsorption spectra in the exciton region were measured on very thin CdS and CdSe single crystals at 77 °K in the field range 1 × 103 to 2.4 × 104 V/cm for both polarizations of incident light with respect to the c‐axis. The electroabsorption spectra exhibit much more details than electroreflection spectra know so far. The variation of peak positions and peak heights with electric field strength is different for different parts of the spectrum. Some of the peaks shift to lower and others o higher energies with increasing field strength. The spectra can be interpreted in terms of a second order Stark shift, field induced line broadening and Franz‐Keldysh type interband oscillations.

The temperature of theFregion deduced from electron number-density profiles

Electron number-density-height profiles of the ionosphere were deduced from ionograms taken at Lindau/Harz during noon intervals and years of high and low solar activity. The curvature of these profiles close to the F2 peak was determined by a parabolic approximation and expressed by the half-thickness Ym of this parabola. These Ym values proved to be proportional to the respective neutral gas temperature at the peak as deduced from satellite drag measurements. The upper and lower limits were ±10%, respectively. This result differed from recent theoretical studies and suggested more detailed studies in this field. The seasonal peak height variation of the F2 layer was shown to mirror the exospheric temperature anomaly. It was concluded that both anomalies might have the same origin, namely, dynamical effects in the ionosphere and exosphere. In completion, data on the heating of the ionosphere during mean geomagnetic disturbances deduced by a lunar tidal analysis of the same real height data were added. A rate of 5.8°K per unit of Ap was found.