Polymer foil applicable to the tilted foil technique

A polymer foil of polyethylene-terephthalate was successfully used for the tilted foil to create nuclear polarization of beta-emitters. The foil was carefully prepared to produce atomic flatness on the surfaces. The resultant smoothness was confirmed with beta-NMR measurements on¹²B and found to be as good as those of carbon foils used previously in the measurements.     

Measurement of metastable-state densities by self-absorption technique

A technique is described for the measurement of metastable-state densities by self-absorption in a plasma. The absorption parameter k₀l is determined from the ratio of the total intensities of two partially self-absorbed lines ending on the level for which one wishes to determine the population. We develop this method for the case of a homogeneous medium for which the emission and absorption lines have Doppler, Lorentz or Voigt profiles. We study the error inherent in this model when the medium is spatially inhomogeneous. We apply this method to the measurement of atomic and ionic metastable concentrations in a highly ionized argon plasma.     

A modified vibration-rotation contact transformation technique

A modification of the unitary operators used in conventional vibration-rotation contact transformation calculations is described and developed. It is shown that this modification leads to substantial and significant simplifications of the existing theory. The modified theoretical development is applied to the calculation of the sextic centrifugal distortion constants of asymmetric rotators, and the recent results of Aliev and Watson are duplicated.     

A modified Feautrier method

A modification of the Feautrier method of solving transfer problems is presented that allows advantage to be taken of such simplifications as isotropic scattering and complete frequency redistribution. The method has timing and storage requirements comparable to integral equation methods, but retains the ease of formulation of differential methods. The case of a two-level atom is treated in detail, and an appropriate generalization is sketched for the treatment of multi-level cases by means of a complete linearization technique.     

A tunnelling correction factor for the modified near-field technique

A tunnelling correction factor is derived for modified near-field scanning. This correction is insensitive to core profile shape and can be accurately applied to fibres with core noncircularity. Examples are given which demonstrate its accuracy for both step- and parabolic-index core fibres.     

Application of accelerated-convergence technique to modified Lanczos calculations

Summary The use of modified Lanczos procedure to obtain the ground-state eigenvalue and eigenvector of the Hamiltonians of physical systems and its subsequent modification for the determination of excited states has been revealed a very efficient and powerful procedure. Nevertheless, when implementing the method, one notices that the convergence of the algorithm is very slow, so that the calculation may become heavy from a computational point of view. The aim of this paper is the proposal of an accelerated-convergence technique (which has already been successfully used in density-of-states calculations), that allows to obtain a faster convergence of the modified Lanczos eigenvalues to the exact ones. The advantages of such a technique are shown through the discussion of some examples.     

一种用于应力测量的复合型超声波探头

为了在应力测量中更好地测量超声波的纵波声速和横波声速，提高测量的精度和准确性，本文研究了一种由两种不同频率的纵波晶片和两处偏振方向相互垂直的横波晶片组成的复合型超声波探头，研究了它的几种组合的发射与接怍ＭＡＳＯＮ等效电路图，并报道了它的一些实验结果。     

A Raman technique applicable for the analysis of the working principle of promoters and inhibitors of gas hydrate formation

We report a Raman technique applicable for the in situ analysis of the development of hydrogen bonds in the liquid water‐rich phase just before the onset of gas hydrate formation. Herewith, the phase transition as well as the working principle of hydrate formation inhibitors and promoters can be analyzed. © 2015 The Authors. Journal of Raman Spectroscopy published by John Wiley & Sons Ltd.     

A modified version of the Methfessel‒Paxton method

A modified version of the method for calculating integrals over the Brillouin zone, which relies on the use of the orthogonal function series, is discussed. It is shown that adoption of the system of Chebyshev’s polynomials makes it possible, while retaining all the advantages of the original scheme, to overcome a number of its disadvantages and to improve the numerical stability in the case of high-degree polynomial approximation, to reduce the number of parameters in the method, and to rule out the development of regions with negative values of the density of states.     

图胞映射的一种改进方法

通过引入新的概念,提出了图胞映射动力系统中瞬态胞的新的分类方法,基于新的分类方法研究了动力系统中不变流形的胞映射逼近问题;并结合计算机的计算速度与内存特点,建立了完成上述压缩分类的有效算法.通过对典型算例Henon映射的应用分析,证实了该方法的有效性. 关键词： 图胞映射方法 不变流形 Henon映射     

图胞映射的一种改进方法

通过引入新的概念，提出了图胞映射动力系统中瞬态胞的新的分类方法，基于新的分类方法研究了动力系统中不变流形的胞映射逼近问题；并结合计算机的计算速度与内存特点，建立了完成上述压缩分类的有效算法.通过对典型算例Henon映射的应用分析，证实了该方法的有效性.     

A nonstandard numerical method for the modified KdV equation

A linearly implicit nonstandard finite difference method is presented for the numerical solution of modified Korteweg–de Vries equation. Local truncation error of the scheme is discussed. Numerical examples are presented to test the efficiency and accuracy of the scheme.     

The INPHARMA technique for pharmacophore mapping: A theoretical guide to the method

During the process of drug discovery, INPHARMA can be used to derive the structure of receptor/lead compound complexes binding to each other with a K_d in the μM to mM range. To be successful, the methodology needs adjustment of various parameters that depend on the physical constants of the binding event and on the receptor size. Here we present a thorough theoretical analysis of the INPHARMA interligand NOE effect in dependence of experimental parameters and physical constants. This analysis helps the experimentalist to choose the correct experimental parameters and consequentially to achieve optimal performance of the methodology.     

A modified Close Proximity method to evaluate the time trends of road pavements acoustical performances

The Close Proximity Index (CPX) measurement method is proposed in the ISO/DIS 11819-2:2011 and it aims to evaluate different road pavements with respect to their influence on traffic noise, under conditions when tyre/road noise dominates. In this paper, a modified CPX-based methodology is presented, in order to improve the usefulness of tyre/road noise measurement in the evaluation of acoustical performances of a road surface, in terms of both temporal and spatial stability and in terms of effectiveness of a mitigation action. In particular, the proposed methodology uses a finer spatial resolution and improves the speed-levels relationship knowledge. Moreover, data variability and uncertainty related to tyre/road noise measurement results are here investigated.This paper is conceived within LEOPOLDO project, developed in Tuscany with the aim to study the acoustical characteristics of six new experimental road surfaces, and the proposed methodology has been applied to some of them. The evaluation of the local possible acoustical inhomogeneities of test pavements and a three years long monitoring of the time evolution of their acoustical performances were required by the project. Finally, a new criterion is proposed to make more reliable comparisons (differential criterion) between different road surface types and to better evaluate the temporal evolution.     

A modified Feautrier method for expanding atmospheres

Rybicki's rearrangement scheme is applied to a plane parallel expanding stellar atmosphere, as solved in the co-moving frame with the Feautrier method by Noerdlinger and Rybicki (NR). The gain in timing requirement is slight, because fewer frequencies are needed in a fluid frame code, but the gain in storage is great, because back-substitution becomes unnecessary. The formulation becomes much simpler, because the rectangular matrices of NR become square. Furthermore, the “interleaving” technique of NR, wherein the mean intensity and fluxlike variables are defined in alternate layers, can be preserved, with the bonus that the local values of the radiation force naturally alternate with those of the mean intensity in the solution vector. The scheme is readily adaptable to non-monotonically varying velocity fields, in contrast to the original formulation.     

Measured lifetimes in mercury using the photon-photon delayed coincidence technique

The photon-photon delayed coincidence technique has been used to measure the 6³P₁, 7³S₁, and 7¹S₀ level lifetimes in mercury atoms. The measured mean lifetimes are 6³P₁(116±5) ns, 7³S₁(7.7±0.4) ns and 7¹S₀(30.5±4.3) ns, respectively.     

An adiabatic theorem applicable to the stark effect

We prove an adiabatic theorem applicable to an atom evolving in a slowly varying electric field. This yields an operational estimate of the tunneling rate even for systems where complex scaling techniques are not applicable.     

A numerical solution of the vibration equation using modified decomposition method

In the present paper the well-known vibration equation for very large membrane with the help of powerful modification of Adomian decomposition method proposed by Wazwaz [A reliable modification of Adomian decomposition method, Applied Mathematics and Computation 102 (1999) 77-86] has been solved. By using initial value, the explicit solutions of the equation for different cases have been derived, which accelerate the rapid convergence of the series solution. The present method performs extremely well in terms of efficiency and simplicity. Numerical results for different particular cases of the problem are presented graphically.     

Modeling the radio and optical/NIR afterglows of GRB 980703: A numerical study

Extensive multi-band afterglow data are available for GRB 980703. Especially, its radio afterglow was very bright and was monitored until more than 1000 days after the trigger time. Additionally, there is no obvious special feature, i.e., no rebrightenings, no plateau, and no special steep decay or slow decay in the multi-band afterglow light curves. All these conditions make GRB 980703 a precious sample in gamma-ray burst research. Here we use the observational data of GRB 980703 to test the standard fireball model in depth. It is found that the model can give a satisfactory explanation to the multi-band and overall afterglow light curves. The beaming angle of GRB 980703 is derived as ∼ 0.23 radian, and the circum-burst medium density is ∼ 27 cm⁻³. The total isotropic equivalent kinetic energy of the ejecta is ∼ 3.8 × 10⁵² ergs. A rest-frame extinction of A _V ∼ 2.5 mag in the host galaxy is also derived.