Volume 34(2) - Summer 2018

Simultaneous thermogravimetry-differential thermal analysis/differential scanning calorimetry (TG-DTA/DSC) is the method with which changes in both the mass and energy of a sample upon heating can be measured simultaneously. From the data obtained, macromolecular information with regard to physicochemical change in the sample can be obtained. However, in order to know what specific kind of reaction takes place, information from other analytical methods is indispensable. For example, when the TG-DTA measurement indicates that an endothermic reaction accompanied by a mass loss takes place, this may suggest that one or more of a number of possible reactions occur, such as dehydration, evaporation, sublimation, decomposition, and reduction. In this case, if the structural formula, decomposition temperature, and content ratio of the absorbed moisture of the sample is available, it would be possible to suggest the kind of reactions that might be taking place. However, if the sample is totally unknown, even supposition is difficult. In this case, if information about structural change to the sample and the chemical species volatized were available from other analytical methods combined with the TG-DTA results, this would help understand the reaction processes taking place in the sample.

Since it is possible to apply zinc to the surface of steel sheet in large quantities, hot-dipped zinc coated steel sheet is used for applications that require long period corrosion resistance, such as automotive bodies, prefab and metal buildings.

Zinc coated steel sheet can be roughly divided into zinc coated steel sheet (Galvanized steel sheet: GI) which is plated by immersing the steel sheet in a molten zinc bath and zinc–iron alloy coated steel sheet (Galvannealed steel sheet: GA) which diffuses the iron in the steel to coated zinc through the boundary of the zinc and steel by heating after plating treatment to make a zinc–iron alloy. GI capable of coating weight of 400 g/m² or more is widely used for applications requiring severe weather resistance, such as outdoor units of air conditioners, guardrails, construction materials, and so on. Since GA whose plating layer is zinc–iron alloy has the futures of that (1) it is easy to form into complex shapes because of harder plating than zinc alone and hardly adhering to the mold at the time of press molding, (2) it has excellent weldability because of its high melting point, (3) since the surface has dense irregularities, it is excellent in paint adhesion because of dense asperities on the surface, In addition to having anticorrosive property of GI, GA has been expanding its use mainly for automobile bodies with high demand for shape design.

Single crystal X-ray structural analysis of proteins includes these steps: expression, crystallization of protein, data collection, phase determination, model building, model fitting, and refinement of the molecular model. When the difficult steps of crystallization and phase determination are overcome, the process of structural analysis can move on to model building and refinement. 

The initial electron density map after phase determination is usually noisy. Therefore, before model building, noise is reduced by density modification methods, such as "solvent flattening" and "histogram matching," resulting in an improved electron density map, which makes the model building step easier. 

In the past, model building was done by making full use of a very expensive graphic work station, such as ones produced by Silicon Graphics. Additionally, the refinement calculation took more than one overnight period in most cases. However, nowadays, due to the increased speed of computers, structural analysis and model building can be carried out on a personal Windows or Mac computer, and refinement can be completed within minutes if things go well. If high-quality, high-resolution data can be obtained, most of the molecular model can be built automatically, thanks to advances in crystallographic software. However, if data resolution necessary for automatic model building cannot be obtained, it is still necessary to manually add amino acid residues one by one to build the model.

Here, construction and refinement of the model in X-ray structural analysis will be explained.

X-ray diffractometry is widely used in R&D and quality control to investigate the crystal structure of materials. It has a diverse range of application, and is used not only for qualitative and quantitative analysis of powder samples, but also to evaluate the aggregate structure of metal materials, analyze the crystal orientation of thin-film samples, and so forth. Previously, individual analysis programs were developed for each measurement and evaluation technique. Multiple applications had to be launched to finish evaluation, and the operation process could be complicated.

The integrated X-ray diffraction software suite SmartLab Studio II solves this problem by combining measurement and analysis functions into a single program. These functions are built on a common platform, which enables consistent and easy execution of tasks such as data display, data transfer when starting analysis, and creation of reports of analysis results. Also, software startup time and the number of logins are minimized, and thus the workflow for the user is greatly improved.

Furthermore, SmartLab Studio II ver. 4 adds a real-time analysis function for simultaneously performing qualitative and quantitative analysis during measurement, and a real-time display function for pole figure and reciprocal space mapping measurement. The following provides details on real-time analysis, and presents examples of measurement.

A pole figure (PF) measurement is an X-ray diffraction (XRD) technique employed for the observation of textures in polycrystalline materials in the form of bulk ceramics, metal complex, thin films, etc, or the analysis of the orientation or domain configuration of epitaxial thin films. A comprehensive explanation of pole figures can be found in the technical article “X-ray thin film measurement techniques” in the Rigaku Journal. However, we often receive questions or requests for technical advice about PF measurements, especially for thin film samples. Users may wonder which of three PF measurement methods should be employed using a SmartLab system equipped with an in-plane axis and a 2D detector. This is the reason for this lecture note. Features of the three possible PF measurements will be reviewed to guide SmartLab users, studying thin film samples. Since a pole figure measurement using an in-plane axis is such a unique and useful technique, it merits a discussion of updated applications using this technique for modern functional materials.

Organic electronics based on organic semiconductors as an active layer have been extensively researched as next-generation electronic devices. To develop the market for organic electronic devices such as integration circuits and sensors, the carrier mobility (hereinafter referred to as the mobility) is an important parameter for device performance and needs to be improved significantly. Additionally, considering applicable organic electronics, organic semiconductors must exhibit the following features: 1) chemical and thermal stabilities during the device fabrication process and in the operating environment, 2) device durability under ambient air and bias stress, and 3) solution-processability. To achieve these requirements, innovations in molecular design technologies are needed.

SmartLab, which was announced as a thin film sample X-ray diffractometer in 2005, is a high-precision goniometer with a high-intensity X-ray source based on an innovative ergonomic design, and is widely used by many users. SmartLab has been updated several times in the 13 years since its launch. This year, an even more sophisticated model of SmartLab was introduced.

In addition to the encoder-controlled-type high-precision horizontal sample mount goniometer featured in previous SmartLab models, this SmartLab offers many new features, including an advanced, safer cabinet; a longer-life high-intensity X-ray source; a multi-dimensional detector, the HyPix-3000, with improved sensitivity; an optical system supporting different types of measurement; and integrated software to control the system.

X-ray Fluorescence Analysis (XRF) has been used in a wide range of fields as an instrumental analysis method that enables quick and easy elemental analysis. Compared with other methods, sample preparation is simpler and analysis accuracy is higher, and therefore it is not only used for quality control but also for research and development. 

Simultix is a simultaneous wavelength dispersive X-ray fluorescence (WDXRF) spectrometer, which can simultaneously measure multiple elements (up to 40) and is widely used as an elemental analyzer for process control such as in steel and cement industries that require high throughput and precision.

Since the release of the first Simultix a half-century ago in 1968, over 1200 Simultix systems have been delivered to customers around the world so far. Improvements have continually been made over these years. The recently released Simultix15 has the most advanced performance, functions and operability to meet diverse and modern needs realized by continued technological innovation.

X-ray fluorescence analysis is well-known as a non-destructive elemental analysis method. Sample preparation for the XRF technique can be performed quickly and easily, especially for solid samples. A wavelength dispersive type X-ray fluorescence spectrometer (WDXRF) has highly precise performance, so WDXRF is used for sample analysis in process and production control in many manufacturing industries. A sequential type WDXRF, which can analyze from oxygen to uranium using default optical configurations, is used for a variety of materials such as in R&D and acceptance inspections, etc. A high-performance WDXRF equipped with a sample stage and a sample observation system can perform small point analysis and area mapping. This function can apply to the inspection for abnormalities and the analysis of inclusions or inhomogeneity in manufacturing products. Thus, WDXRF has expanded its application field beyond conventional elemental analysis.

Rigaku’s ZSX Primus family of WDXRF spectrometers is composed of the following instruments: ZSX Primus IV, a high-performance XRF with tube-above optics; ZSX Primus, high-performance with tube-below optics; and ZSX Primus III+, standard XRF with tube-above optics. Because all of these spectrometers use a sample holder system during measurement, sample specimens must be smaller than the dimensions of a sample holder. There are, however, numerous demands for WDXRF analysis to be performed on samples in their original product size without any processing. In order to resolve these sample size limitations, the new ZSX Primus 400 has been developed based on the earlier ZSX400 and released as a member of the ZSX Primus family, incorporating many of the latest functions of ZSX Primus IV.

The benchtop wavelength dispersive X-ray fluorescent spectrometer Supermini200 and its predecessors have been on the market since 2000 and are being used on every continent in the world for research and industrial applications. Since its inception, demands for controlling lower levels of phosphorous (P), sulfur (S) and chlorine (Cl) have been on the rise. To meet these challenges, the Supermini200 is now available with the highly sensitive analyzing crystal RX9 realizing 0.1 ppm lower limits of detection (LLD) for P, S and Cl in hydrocarbon-based samples.