On some discretization methods for solving a linear matrix ordinary differential equation

In this paper, some discretization methods are considered for solving a linear matrix ordinary differential equation. Discussion is focused on a family of one step methods which include Euler, backward Euler, and Crank–Nicolson schemes as special cases, as well as the Runge–Kutta methods. As an illustration, detailed convergence and error analysis are given for the family of one step methods. Some numerical examples are provided to show the good performance of the methods.     

A family of eight-step methods with vanished phase-lag and its derivatives for the numerical integration of the Schr?dinger equation

A family of tenth algebraic order eight-step methods is constructed in this paper. For this family of methods, we require the phase-lag and its first, second and third derivatives to be vanished. Three alternative methods are proposed which satisfy the above requirements. An error analysis and a stability analysis is also investigated in this paper and a comparison with other methods is also studied. The new proposed methods are applied for the numerical solution of the one dimensional Schrödinger equation. The efficiency of the new methodology is proved via theoretical analysis and numerical applications.     

Exponentially - Fitted Multiderivative Methods for the Numerical Solution of the Schrödinger Equation

In this paper exponentially fitted multiderivative methods are developed for the numerical solution of the one-dimensional Schrödinger equation. The methods are called multiderivative since uses derivatives of order two and four. An application to the the resonance problem of the radial Schrödinger equation indicates that the new method is more efficient than other similar well known methods of the literature.     

A Family of Trigonometrically-Fitted Symmetric Methods for the Efficient Solution of the Schrödinger Equation and Related Problems

In this paper a family of trigonometrically-fitted symmetric ten-step methods for the efficient solution of the Schrödinger equation and related problems is presented. Construction and stability analysis of the new methods is described. Numerical results obtained for the resonance problem of the one-dimensional Schrödinger equation show the efficiency of the new methods when they are compared with known methods in the literature.     

Symplectic Methods of Fifth Order for the Numerical Solution of the Radial Shrödinger Equation

In this paper the numerical solution of the radial Shrödinger equation via new proposed symplectic-schemes is investigated. In particular, the radial Schödinger equation is transformed into Hamiltonian canonical form and is solved via symplectic integrators. Based on this approach, fifth-order methods are proposed. We compare these methods with well-known existing symplectic methods. The numerical results show the efficiency of the proposed method.     

New P-Stable Eighth Algebraic Order Exponentially-Fitted Methods for the Numerical Integration of the Schrödinger Equation

A family of P-stable high algebraic order exponentially-fitted methods for the numerical solution of the Schrödinger equation is developed in this paper. Numerical illustration to the resonance problem of the radial Schrödinger equation indicates that the new proposed methods are generally more efficient than the previously developed exponentially-fitted methods of the same kind.     

Regression models with process variables and parallel blocks of raw material measurements

The topic of this paper is regression models based on designed experiments, where additional spectroscopic measurements are also available. This particular case describes a situation with two spectral blocks with no natural order: The blocks are parallel. Three methods are described, which combine least squares regression of the design variables with PCA or PLS on the spectra. The methods properties are explored in two simulation studies based on real experiments. The results show that the methods are equal when it comes to prediction, but interpretability varies. One of the methods, LS‐ParPLS, is especially interesting when it comes to interpretability because it splits the spectral information into two parts; information that is common in both blocks and information that is unique for each block. Copyright © 2008 John Wiley & Sons, Ltd.     

Determination of 241Am in Environmental Samples: A Review

The determination of ²⁴¹Am in the environment is of importance in monitoring its release and assessing its environmental impact and radiological risk. This paper aims to give an overview about the recent developments and the state-of-art analytical methods for ²⁴¹Am determination in environmental samples. Thorough discussions are given in this paper covering a wide range of aspects, including sample pre-treatment and pre-concentration methods, chemical separation techniques, source preparation, radiometric and mass spectrometric measurement techniques, speciation analyses, and tracer applications. The paper focuses on some hyphenated separation methods based on different chromatographic resins, which have been developed to achieve high analytical efficiency and sample throughput for the determination of ²⁴¹Am. The performances of different radiometric and mass spectrometric measurement techniques for ²⁴¹Am are evaluated and compared. Tracer applications of ²⁴¹Am in the environment, including speciation analyses of ²⁴¹Am, and applications in nuclear forensics are also discussed.     

Hairs,criminals, moonrocks,metals diseases,polluters! Where next for nuclear analytical chemistry?

Nuclear methods of analysis have advanced dramatically in recent years, and in many ways, techniques that once were viewed as a scientific curiosity and the toys of a few scientists working in large nuclear research establishments, are now semi-routine and can be applied even by young students. Large amounts of good analytical data are outputted from instruments having sophisticated embedded software. It is interesting to speculate on the directions that nuclear analytical techniques may take next: whether more multielement; more automation for vastly larger sample suites; extension to minor and major components of samples as well as trace components; coupling of nuclear methods to hyphenated methods. However, in some respects the resources needed to continue to develop and apply radioanalytical methods are on the wane: reactors and accelerators are being closed and fewer radiochemical specialists are being trained. The open question, is whether instrumental analysis techniques will offer more and better results with less effort, or be less equipment intensive? In this paper some personal reflections on nuclear actcivation methods and their trends are presented and discussed. Some mileposts in the development of the field and some unique and interesting applications (as implied by the paper title) are cited and discussed.     

Review of Sub-Microliter (Nanoliter) Injection Techniques in Liquid Chromatography

Abstract

In liquid chromatography with “low-dispersion methods”, there is an increasing need to reproducibly inject nanoliter sample volumes. Low-dispersion methods produce very narrow peaks because of short column length, narrow column bore, small particle packing, low particle surface area, open tubular configuration, or combinations of these parameters.

This paper reviews methods used for sub-microliter injections for use with these low-dispersion liquid chromatography methods. Some nanoliter injection methods for open-tubular electrophoresis are also described.     

Symplectic Methods for the Numerical Solution of the Radial Shrödinger Equation

In this paper new symplectic-schemes for the numerical solution of the radial Shrödinger equation are proposed. In particular, symplectic integrators for Hamiltonian systems have been developed. Based on this approach, second- and third-order methods are proposed. These methods are more accurate than the existing ones. We compare these methods not only with the existing symplectic methods, but also with a classical Runge–Kutta–Nyström method.     

Radon emanometric technique for 226Ra estimation

Studies on natural background radiation show that the major contribution of radiation dose received by population is through inhalation pathway vis-à-vis contribution from radon (²²²Rn) gas. The immediate parent of radon being radium (²²⁶Ra), it is imperative that radium content is measured in the various matrices that are present in the environment. Among the various methods available for the measurement of radium, gamma spectrometry and radiochemical method are the two extensively used measurement methods. In comparison with these two methods, the radon emanometric technique, described here, is a simple and convenient method. The paper gives details of sample processing, radon bubbler, Lucas cell and the methodology used in the emanometric method. Comparison of emanometric method with gamma spectrometry has also undertaken and the results for a few soil samples are given. The results show a fairly good agreement among the two methods.     

New optimized two-derivative Runge-Kutta type methods for solving the radial Schrödinger equation

This paper focuses on adapted two-derivative Runge-Kutta (TDRK) type methods for solving the Schrödinger equation. Two new TDRK methods are derived by nullifying their phase-lags and the first derivatives of the phase-lags. Error analysis is carried out by means of asymptotic expressions of the local errors. Numerical results are reported to show the efficiency and robustness of the new methods in comparison with some RK type methods specially tuned to the integration of the radial time-independent Schrödinger equation with the Woods–Saxon potential.     

A family of multiderivative methods for the numerical solution of the Schrödinger equation

A family of multiderivative methods with minimal phase-lag are introduced in this paper, for the numerical solution of the Schrödinger equation. The methods are called multiderivative since uses derivatives of order two, four or six. Numerical application of the new obtained methods to the Schrödinger equation shows their efficiency compared with other similar well known methods of the literature.Active Member of the European Academy of Sciences and Arts     

The quantitative determination of fission and nuclear reaction products

Definitions are given to the terms “per cent atom burn-up” and “per cent atoms consumed” as applied to nuclear fuel analysis at the Argonne National Laboratory. The radiochemical and analytical methods which have been adapted and developed especially for this type of analysis are discussed. The analysis of nuclear reaction products by paper chromatographic methods and scintillation spectrometry is emphasised and demonstrated.     

State Of The Art For The Examination Of Uv Spectra Of Waters And Wastewaters

Abstract

The paper reviews different mathematical methods for the exploitation of the UV spectrum of waters and wastewaters, including the interferences treatment. After the presentation of simple methods and their limits, several global approaches using a matricial presentation of the data are discussed. The usual methods, statistical multivariate or deterministical procedures are not relevant. Nevertheless, other methods based on the restitution of interferences effect as a combination of fixed basic signals, either mathematical or physical, are available. The first procedure is semi-deterministic without chemical knowledge of the interferences nature or effects-and only mathematical hypothesis on the spectrum shape-while the second is a more qualitative method based on the fact that most of interferences can be resumed as a linear combination of few independent spectra with chemical signification. These considerations underline the importance of direct examination of UV spectra of waters and wastewaters.     

Symmetric Eighth Algebraic Order Methods with Minimal Phase-Lag for the Numerical Solution of the Schrödinger Equation

In this paper some new eighth algebraic order symmetric eight-step methods are introduced. For these methods a direct formula for the computation of the phase-lag is given. Based on this formula, the calculation of free parameters is done in order the phase-lag to be minimal. The new methods have better stability properties than the classical one. Numerical illustrations on the radial Schrödinger equation indicate that the new method is more efficient than older ones.     

饲料及食品中玉米赤霉烯酮检测方法研究进展

玉米赤霉烯酮是一种由镰刀菌分泌,广泛污染谷物类粮食作物的真菌毒素,具有雌激素干扰和肝脏、免疫、遗传毒性.玉米赤霉烯酮污染不仅极大危害农牧业发展,更引发严重的食品安全问题.因此建立准确、灵敏的玉米赤霉烯酮检测方法对控制谷物及农副产品中毒素含量至关重要.就目前饲料及食品中常用的玉米赤霉烯酮检测方法进行综述,以供参考借鉴.     

Paper conservation methods: a literature review

The main paper conservation methods are presented, classified in the following categories: preparation of the intervention, disinfestation and disinfection/sterilization, surface/dry cleaning, wet cleaning, chemical stabilization, paper repairs, consolidation and strengthening. Treatment documentation is also discussed. The targets, the historical aspects, the general principles, the materials and equipment, the acceptance and criticism pertaining to each method are briefly reviewed, and the most important research for their evaluation is presented. Several paper stabilization strategies, such as deacidification and iron gall ink stabilization, applicable to paper are elucidated. Specific consolidation and strengthening methods for paper, such as lamination and paper splitting are also discussed. The review mainly focuses on the established methods, but experimental, abandoned or insufficiently documented methods are also included. Shortcomings and limitations of several methods were found in the literature, concerning health issues, limited effectiveness, adverse side-effects on the treated artefacts and restricted applicability.     

Precision of integral methods for the determination of the kinetic parameters

In this paper, a systematic analysis of the errors involved in the determination of the kinetic parameters (including the activation energy and frequency factor) from five integral methods has been carried out. The integral methods analyzed here are Coats-Redfern, Gorbachev, Wanjun-Yuwen-Hen-Zhiyong-Cunxin, Junmeng-Fusheng-Weiming-Fang, Junmeng-Fang and Junmeng-Fang-Weiming-Fusheng method. The results have shown that the precision of the kinetic parameters calculated by the different integral methods is dependent on u (E/RT), that is, on the activation energy and the average temperature of the process.