Comments on “A study of amorphous Ti–Ni alloys by X-ray photoelectron spectroscopy”

Recently, Seabolt et al. have published a paper [M.A. Seabolt, W.R. Ogden, A.R. Chourasia, A. Ishida, J. Electron Spectrosc. Relat. Phenom. 135 (2004) 135] in which – among others – they determine the density of states (DOS) in some materials by electron spectroscopic means. The experimental work they do is impressive and they do a pioneering work with trying to make a quantitative analysis of the density of states. However, the oversimplified data evaluation method strongly degrades the value of their work. The authors state (but do not show) that the results of a complementary analysis support their conclusions, but the principle and some technical mistakes during the data evaluation make some results of the work unreliable. Below, their data analysis method is scrutinized and it is shown that the quantitative information they derive is more likely a data evaluation artifact, stemming from the inherent features of the Shirley-type background removal, rather than a quantitative measure of the DOS.     

Comments on “Scale-free networks without growth”

In [Y.-B. Xie, T. Zhou, B.-H. Wang, Scale-free networks without growth, Physica A 387 (2008) 1683-1688], a nongrowing scale-free network model has been introduced, which shows that the degree distribution of the model varies from the power-law form to the Poisson form as the free parameter α increases, and indicates that the growth may not be necessary for a scale-free network structure to emerge. However, the model implicitly assumes that self-loops and multiple-links are allowed in the model and counted in the degree distribution. In many real-life networks, such an assumption may not be reasonable. We showed here that the degree distribution of the emergent network does not obey a power-law form if self-loops and multiple-links are allowed in the model but not counted in the degree distribution. We also observed the same result when self-loops and multiple-links are not allowed in the model. Furthermore, we showed that the effect of self-loops and multiple-links on the degree distribution weakens as α increases and even becomes negligible when α is sufficiently large.     

A note on forced vibrations of a clamped rectangular plate

Simple polynomial approximations and Galerkin's method are used to determine the response of a thin, elastic, rectangular plate clamped along the boundary and subjected to sinusoidal excitation. It also is shown that a one-term polynomial solution yields good accuracy in the case of a rectangular plate with simply supported edges.     

Direct laser patterning of self-assembled monolayer using elliptical laser beams: A theoretical parametric study

A theoretical quantitative analysis of processing parameters for application of an elliptical laser beam to achieve maximum patterning area is the focus of this study. Direct laser patterning (DLP) of self-assembled monolayers (SAM) is achieved by localized heating of the sample above the SAM desorption temperature. Through use of elliptical laser beams in the present work, three goals are achieved by analyzing the heat diffusion model and related thermo-kinetics model: (1) optimal working conditions (combination of laser power, scanning velocity and aspect ratio) for DLP to produce maximum feature size, or highest processing velocity at a given power; (2) identification of conditions that reduces the potential thermal damage to the substrate; (3) shedding light on issues related to uniformity or homogeneity of heating a substrate using an elliptical laser beam. A heat diffusion model is employed to provide the resulting surface temperature caused by elliptical laser beams, and the coupled thermo-kinetics model is used to determine the final SAM coverage generated by DLP. Parametric analysis revealed that 70–150 mW can be used to pattern feature sizes in the range of 2–10 times of equivalent circular beam size. It is also found that each elliptical laser beam has a unique optimal aspect ratio to result in the widest feature size for a given laser power and scanning velocity. The edge transition width increases with an increase of the aspect ratio. Keeping the aspect ratio of elliptical laser beam small (i.e. β<20), a sharp edge definition could be obtained; if an aspect ratio larger than 30 is used, a surface with gradual edge definition could be obtained.     

Comments on “A new method for phase extraction from a single fringe pattern”

We comment on the recent paper by Tay et al. [Opt. Commun. 239 (2004) 251], in which a phase extraction method from a single fringe pattern is proposed. Their claimed “new method” is based on a couple of assumptions on the behavior of the fringe pattern, which are closely related to the well-known Fourier-transform technique.     

Experimental study on the symmetric modes of vibration of a four bolt clamped square plate

The response of structural components excited by turbulent flow noise depends on the natural resonance frequencies and displacement modes of those components. An experimental program is described which determined those resonance frequencies and modes for a flat plate clamped in the middle of its four sides and also for the case when one of the four bolts had failed. Thirty-three resonances in the range 30·5 to 736 Hz have been identified for the four-bolt normal operation and forty-two in the range 12·5 to 496·1 Hz for the three-bolt accidental situation. Of particular interest to the turbulent flow noise response, the modes symmetrical to the $\text{x-y}$ and diagonal axes have been identified and classified into a two-dimensional matrix form for the $\text{mn + nm}$ and $\text{mn - nm}$ modes combination ($\text{m}$ and $\text{n}$ being the pure modes along the $\text{x-y}$ axis).     

Adaptive non-linear control of a clamped rectangular plate with PZT patches

The dynamic behavior and control of a clamped rectangular plate with bonded piezoelectric ceramic patches are investigated in this paper. The dynamic behavior is studied experimentally, showing that the plate exhibits dense modes, varying residual stress and non-linearity. An adaptive non-linear control scheme is then presented, which introduces a non-linear function into the normal adaptive feedforward control to non-linearize a reference signal. Vibration reductions using both the normal adaptive feedforward control and the adaptive non-linear control are compared in the cases of sinusoidal excitations at the first nine modal frequencies of the plate and a swept-frequency harmonic excitation below 100 Hz, indicating that the adaptive non-linear control can suppress not only the fundamental frequency vibration that the normal adaptive feedforward control can only attenuate, but also its higher harmonic components. Significant vibration reduction achieved by the adaptive non-linear control demonstrates its validity and reliability.     

Response to “Comments on An analytical study of sound transmission through unbounded panels of functionally graded materials”

The solution expression in Eq. (28) is clarified and corrected.     

Nonautonomous “rogons” in the inhomogeneous nonlinear Schrödinger equation with variable coefficients

The analytical nonautonomous rogons are reported for the inhomogeneous nonlinear Schrödinger equation with variable coefficients in terms of rational-like functions by using the similarity transformation and direct ansatz. These obtained solutions can be used to describe the possible formation mechanisms for optical, oceanic, and matter rogue wave phenomenon in optical fibres, the deep ocean, and Bose-Einstein condensates, respectively. Moreover, the snake propagation traces and the fascinating interactions of two nonautonomous rogons are generated for the chosen different parameters. The obtained nonautonomous rogons may excite the possibility of relative experiments and potential applications for the rogue wave phenomenon in the field of nonlinear science.