Scientific Review: New Software for Neutron Scattering Data Visualization

New software for neutron scattering data visualization, reduction, and analysis is being developed at IPNS through collaboration between IPNS and the University of Wisconsin-Stout. Recent advances in this Integrated Spectral Analysis Workbench (ISAW) package include: 1) a data analysis package for Single Crystal Diffractometers, 2) a data reduction package for small angle scattering, 3) wizards-a new method of operation which allows the user to step through a series of input forms to do a complete analysis, and 4) a newly designed set of viewers which work with basic data arrays and thus do not require the more complex data objects used for the first generation of viewers.     

News & views: New Scientific Opportunities at the European Synchrotron Radiation Facility

Approximately 400 participants learned about the latest scientific capabilities at the Stanford Synchrotron Radiation Lightsource (SSRL) and Linac Coherent Light Source (LCLS) during the 2013 Users' Meeting at the SLAC National Accelerator Laboratory, October 1–4, 2013. The Users' Meeting included more than a dozen workshops as well as scientific awards, poster presentations, and talks on the latest scientific trends, challenges, and opportunities.     

Various Software Packages for Analysis of Nuclear Magnetic Resonance Spectroscopic Data

The magnetic resonance spectroscopy (MRS)results are greatly influenced by reconstruction of the spectrum and quantitative analysis.Because of this requirement a number of programs dedicated to MRS data analysis were developed.The selection and use of appropriate software is crucial not only in clinical proce-dures,but also while carrying out scientific research.The choice of the software to suit the user's needs should be based on the analysis of the functionality of the program.It is particularly important from the user's viewpoint to identify what data can be loaded and processed in the program.The specific programs allow the user different degree of control over analysis parameters.Moreover,the programs for MRS data analysis differ in terms of the applied signal processing algorithms.The aim of this work,therefore,is to review available packages designed for MRS data analysis,taking into account their capabilities and limitations.     

Scientific Review: A New Epithermal Neutron Diffractometer at KENS (EXCED)

Neutron scattering experiments on highly absorbing materials like boron (10B), cadmium (113Cd), rare earths (Sm, Eu, Gd, Dy), etc., are extremely difficult to perform and have so far discouraged research activities on relevant compounds. However, recent topical phenomena such as charge ordering and orbital ordering have highlighted the importance of studying 4f-electron systems and raised a large demand for neutron scattering studies. Unfortunately, the preparation of isotope enriched (weakly absorbing) samples are costly, and very often the large amount of sample required for experiments can not be produced. An alternative way consists of reducing the absorption cross-section _a by utilizing epithermal neutrons of the order of several eV.     

Scientific Review: Spectroscopy at IPNS: Recent Instrumental Upgrade and Scientific Highlights

IPNS has four neutron spectrometers: two chopper spectrometers, HRMECS and LRMECS, and two crystal-analyzer spectrometers, QENS and CHEX. At the outset, HRMECS, LRMECS, and QENS (preceded by CAS in the 1980s) were fully users-dedicated instruments. CHEX was an add-on and has been a prototype for pilot experiments and for further development. Over the years, steady incremental improvements have been made on these spectrometers. Recently, QENS and HRMECS have undergone substantial upgrade both in hardware and software. Here, we describe the design and operation of QENS and HRMECS and illustrate their scientific capabilities by selected examples. Other details concerning IPNS' spectrometers are given elsewhere [1].     

Post Scriptum: Quantum Century and Our International Collaboration in Quantum Physics

Journal of Russian Laser Research - We present a short review of the history of researches in quantum and laser physics at the Lebedev Physical Institute and mention some aspects of international...     

X射线荧光分析数据处理软件的研究和应用

最小二乘法回归线性方程Ｙ＝ＡＸ＋Ｂ，结合Ｘ射线荧光分析数据的特点，用ＢＡＳＩＣ语言编写应用软件。     

近红外光谱分析技术的一些数据处理方法的讨论

介绍了近红外光谱分析的技术原理,常用的几种建模方法以及各自的特点。同时,阐述了光谱的预处理,其中的小波变换方法是一种新的数学工具,有着广泛的应用前景。     

Scientific Review: Polyamorphism and Extreme Environments on GLAD

Given that glasses are not in thermodynamic equilibrium, they may form a continuity of structures depending on small variations in fabrication. However, by analogy with crystallography, the current meaning of polyamorphism refers to the existence of two (or more) very different forms of an amorphous material which are linked via a first order phase transition. The arguments for this rare phenomenon are based largely on the success of two state models in explaining the density maxima (and other theromodynamic properties) that occur in some materials. Glasses currently termed "polyamorphic" include germania, silica, water, yittra-alumina, and triphenolphosphite (TPP), among others. The study of these glasses has formed a significant part of the research on the Glass, Liquid and Amorphous Materials Diffractometer (GLAD) at IPNS in the past few years.     

Scientific Review: Maps and Magnetism in Single Crystals

The MAPS spectrometer at ISIS is a direct geometry instrument that has been designed to measure coherent excitations in single crystals. Knowledge of the momentum, Q, and energy, _?, dependent spectrum of excitations in a single crystal permits the most exacting tests of models for the interactions in a material. For example, the imaginary part of the generalized magnetic susceptibility, _χ'' (Q, ?), contains the full information of the spin-spin correlation functions in a magnetic material from which the strength, range, and symmetry of the magnetic interactions can be determined. This quantity is directly measured by inelastic neutron scattering.     

Scientific Review: ENGIN-X: A Fully Refined Diffractometer Designed Specifically for Measurement of Stress

Neutron stress measurement is a non-destructive technique that provides insights into strain and stress fields deep within engineering components and structures. As such, it has become an increasingly important tool within engineering, leading to improved manufacturing processes to reduce stress and distortion as well as to the definition of more precise structural integrity lifing procedures. Furthermore, it is often the only non-destructive means of measuring the stress state deep within engineering components and structures under conditions (temperature, stress, atmosphere, etc.) representative of those which might be experienced in service.     

Scientific Review: ISIS Second Target Station: Overview and Progress

April 8, 2003 was an important date in the development of the ISIS facility at the Rutherford Appleton Laboratory, when formal approval for the construction of a Second Target Station was announced in a press release by the U.K. Minister for Science and Innovation. This major new investment (£100M) will extend the capability and capacity of ISIS. It will be optimized for the production of cold neutrons, and in particular will enhance the facilities at ISIS and provide exciting new opportunities in the key areas of soft matter, bio-materials, advanced materials, and nano-technology. Taking one in five pulses from the ISIS synchrotron, the lower proton power (48kW) and low repetition rate (10hz) will enable the use of a compact and well-coupled target, moderator, and reflector assembly for the efficient production of long wavelength neutrons with a particularly broad range of simultaneously usable wavelengths.     

一种中药指纹图谱自适应提取方法及软件实现

基于VC++6.0和OpenCV1.0的自主开发界面,应用光谱图像检测原理,设计出了一套适用于中药光谱图像检测系统并能快速获取中药荧光指纹图谱的数据处理软件。同时,成功将该软件应用于自主研发的中药光谱图像检测系统中作为控制及处理模块,并利用其对鹿茸等中药材进行了实际检测,证明了系统的可靠性和准确性。该软件可以同时绘制多达8个中药样品或者8个样品间任意组合的光谱立方体在同一坐标中拟合的特征光谱曲线,从而对样品进行真伪鉴别和品种鉴定,具有操作简便,处理速度快,兼容性好等特点。     

Emerging Theory,Materials, and Screening Methods: New Opportunities for Promoting Thermoelectric Performance

High‐performance thermoelectric materials have attracted immense interest due to the capability of directly converting thermal energy into electrical energy. The correlation and inherent complexity between the thermoelectric parameters pose serious challenges to improving the materials’ thermoelectric performance. Herein, the emerging novel theories in the field of thermoelectrics are summarized, such as the coherent phonon, nanophononic metamaterial, rattling effect, topological phonon, and topological electron. The impacts of these new concepts on thermoelectric performance are then reviewed. Finally, a number of promising thermoelectric materials such as one‐dimensional nanowires, two‐dimensional layered materials, and nanomesh structures are discussed. The advanced understanding of thermal and electrical transport properties in thermoelectric materials is presented herein, providing new opportunities for improving thermoelectric performance.     

用科学探究的方法进行新课教学的尝试——“向心力、向心加速度”的教学

现代教育理论认为"科学探究是科学学习的核心","学科学的中心环节是探究.学生们应该在积极地参与科学探究的过程中逐渐对自然界有所认识.对从学生们所亲历的事物中产生的一些实际问题进行探究,是科学教学所要采取的主要做法","通过做科学(即‘科学探究'活动)来学科学".在<高中物理(试验修订本)>的使用中我们越来越体会到上述教育思想在新教材的编写中已有比较明显的体现.科学探究是以科学方法为指导的,为此加强科学方法的教育也就成了新教材的重要特点之一.     

Energetic nano-materials: Opportunities for enhanced performances

This paper deals with the contribution of nano-materials to the contemporary pyrotechnics science. The breakthroughs in this domain are illustrated by several examples of energetic nano-materials recently studied in our laboratory.The solidification of energetic phases in a porous matrix (Cr₂O₃) was used to prepare and to stabilize at nano-scale explosive particles. The thermo-chemical behaviour of RDX nano-particles strongly differs from the one of micron-sized RDX. For instance, the temperature at which the decomposition occurs is significantly lowered and the melting point is removed. The effect of the decomposition of RDX nano-particles on the matrix in which they are trapped was observed for the first time by the atomic force microscopy.The Cr₂O₃/RDX nano-composite materials were mixed with aluminium nano-particles in order to formulate gas-generating nano-thermites (GGNT). The combustion of GGNT involves a synergy mechanism in which the decomposition of RDX nano-particles fragments the Cr₂O₃ matrix and primes the thermite reaction.“Classical” nano-thermites were obtained by mixing nano-particles (diameter <100 nm) of metallic oxides (WO₃) with a reducing metal (Al). These materials were used to demonstrate that nano-particles (i) significantly lower the ignition delay time and (ii) remarkably increase the combustion rate.Finally, pure RDX nano-particles are prepared by a continuous process of crystallization.