Zhihong Li

1. Low-rank coals generally contain relatively high moisture, volatile matter, and oxygen-containing functional groups. The development of their pore structure is closely related to adsorption, dif...

An innovative dual-thickness semi-transparent beamstop designed to enhance the performance of small-angle X-ray scattering (SAXS) experiments is introduced. This design integrates two absorbers of differing thicknesses side by side into a single attenuator, known as a beamstop. Instead of completely stopping the direct beam, it attenuates it, allowing the SAXS detector to measure the transmitted beam through the sample. This approach achieves true synchronization in measuring both scattered and transmitted signals and effectively eliminates higher-order harmonic contributions when determining the transmission light intensity through the sample. This facilitates and optimizes signal detection and background subtraction. This contribution details the theoretical basis and practical implementation of this solution at the SAXS station on the 1W2A beamline at the Beijing Synchrotron Radiation Facility. It also anticipates its application at other SAXS stations, including that at the forthcoming High Energy Photon Source, providing an effective solution for high-precision SAXS experiments.

Wide-angle X-ray scattering (WAXS) based upon synchrotron radiation is ideal for the in situ study of crystal structural changes during heating at high temperatures. This contribution describes a small furnace for in situ WAXS. The furnace has a wide coverage of scattered/diffracted angle from 0 to 135°, heats samples from room temperature to 1000 °C at 20 °C/min, and is suitable for in situ WAXS and radial distribution function of materials. Temperature calibration and safety verification are provided. The use of the furnace is demonstrated by in situ WAXS for the carbonization of bituminous coal.

Carbonisation is an important way of comprehensive utilisation of coal. In this short contribution, the application of wide angle X-ray scattering (WAXD) and radial distribution function (RDF) in coal carbonisation research is briefly reviewed and prospected. General WAXD analysis can only provide basic geometrical structural parameters of crystals in the sample; while RDF derived from WAXD by Fourier transform can give further detailed structural parameters of coordination of atoms in sample. The application of RDF in coal science has been reported in offline static studies, but not in-situ studies. Here, a new ideal to perform in-situ RDF study on coal carbonisation is presented, which is based on a powerful synchrotron radiation platform with a proper detector and a high-temperature furnace. Thus, it is expected to obtain the fine dynamic structural evolution characteristics of coal during carbonisation.