分类: 核科学技术 >> 粒子加速器 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: Identification and characterization of L-, D- and DL- penicillamine were demonstrated by Terahertz time-domain spectroscopy (THz-TDS). To understand the physical origins of the low frequency resonant modes, the density functional theory (DFT) was adopted for theoretical calculation. It was found that the collective THz frequency motions were decided by the intramolecular and intermolecular hydrogen bond interactions. Moreover, the quantification of penicillamine enantiomers mixture was demonstrated by a THz spectra fitting method with a relative error of less than 3.5%. This technique can be a valuable tool for the discrimination and quantification of chiral drugs in pharmaceutical industry.
分类: 核科学技术 >> 粒子加速器 提交时间: 2023-06-18 合作期刊: 《Nuclear Science and Techniques》
摘要: With the spatial coherence of X-rays and high flux and brightness of the 3rd generation synchrotron radiation facility, X-ray phase contrast microscopy (XPCM) at Shanghai Synchrotron Radiation Facility (SSRF) can provide high resolution dynamic imaging of low electron density materials in principle. In this paper, we investigated the cavitation and water-refilling processes in rice and bamboo leaves utilizing XPCM at SSRF. The occurrence of xylem cavitation was recorded in vivo. The study also revealed that under different dehydration conditions, cavitation occurs in different degrees, and therefore, the refilling process is different. The results demonstrate that SSRF can provide high enough fluxes to study dynamic processes in plants in real-time, and XPCM is expected to be a promising method to reveal the mechanisms of cavitation and its repair in plants nondestructively.
分类: 核科学技术 >> 辐射物理与技术 提交时间: 2023-11-22
摘要: Full-field transmission X-ray microscopy (TXM) is a powerful nondestructive three-dimensional (3D) imaging method with a nanoscale spatial resolution that has been used in most synchrotron facilities worldwide. An in-house-designed TXM system was constructed at the BL18B 3D Nanoimaging beamline at the Shanghai Synchrotron Radiation Facility. The beamline operates from 5 to 14 keV and enables 20 nm spatial resolution imaging. The characterization details of the beamline are described in this paper. The performances in terms of spatial resolution, nano-CT, and nano-spectral imaging of the TXM beamline are also presented in this article.
分类: 物理学 >> 电磁学、光学、声学、传热、经典力学和流体动力学 提交时间: 2023-11-16
摘要: A new X-ray imaging and biomedical application beamline (BL13HB) has been implemented at the Shanghai Radiation Synchrotron Facility (SSRF) as an upgrade to the old X-ray imaging and biomedical application beamline (BL13W1). This is part of the Phase II construction project of the SSRF. The BL13HB is dedicated to 2D and 3D static and dynamic X-ray imaging, with a field of view of up to 48.5 5.2 mm2 and spatial resolution as high as 0.8 m. A super-bending magnet is used as the X-ray source in BL13HB, which has a maximum magnetic field of 2.293 T. The energy range of monochromatic X-ray photons from a double-multiplayer monochromator was 8-40 keV, and the white beam mode was provided on the beamline for dynamic X-ray imaging and dynamic X-ray micro-CT. While maintaining the previous experimental setup of BL13W1, new equipment was added to the beamline experimental station. The beamline is equipped with different sets of X-ray imaging detectors for several experimental methods such as micro-CT, dynamic micro-CT, and pair distribution function (PDF). The experimental station of BL13HB is designed specifically for various in situ dynamic experiments, and BL13HB has been open to users since June 2021.