43 results about "X-ray absorption fine structure" patented technology

This disclosure presents systems for x-ray absorption fine structure (XAFS) measurements that have x-ray flux and flux density several orders of magnitude greater than existing compact systems. These are useful for laboratory or field applications of x-ray absorption near-edge spectroscopy (XANES) or extended x-ray fine absorption structure (EXFAS) spectroscopy. The higher brightness is achieved by using designs for x-ray targets that comprise a number of aligned microstructures of x-ray generating materials fabricated in close thermal contact with a substrate having high thermal conductivity. This allows for bombardment with higher electron density and / or higher energy electrons, leading to greater x-ray brightness and high flux. The high brightness x-ray source is then coupled to an x-ray reflecting optical system to collimate the x-rays, and a monochromator, which selects the exposure energy. Absorption spectra of samples using the high flux monochromatic x-rays can be made using standard detection techniques.

This invention discloses a method and apparatus for x-ray techniques using structured x-ray illumination for examining material properties of an object. In particular, an object with one or more regions of interest (ROIs) having a particular shape, size, and pattern may be illuminated with an x-ray beam whose cross sectional beam profile corresponds to the shape, size and pattern of the ROIs, so that the x-rays of the beam primarily interact only with the ROIs. This allows a greater x-ray flux to be used, enhancing the signal from the ROI itself, while reducing unwanted signals from regions not in the ROI, improving signal-to-noise ratios and / or measurement throughput. This may be used with a number of x-ray measurement techniques, including x-ray fluorescence (XRF), x-ray diffraction (XRD), small angle x-ray scattering (SAXS), x-ray absorption fine-structure spectroscopy (XAFS), x-ray near edge absorption spectroscopy, and x-ray emission spectroscopy.

Negative active materials include vanadium-based oxides to achieve outstanding safety and cycle life characteristics in non-aqueous lithium secondary batteries. A small portion of vanadium is replaced by the second metal to improve the stability of the vanadium-based oxide lattice and maintain the capacity of the negative electrode active material. When measuring the extended X-ray absorption fine structure, the free edge energy peak of the negative active material is between about 5350 eV and about 5530 eV.

The invention discloses a method for preparing a test sample for synchrotron radiation X-ray absorption fine structure of a hydrogen storage material, which relates to the technical field of hydrogen storage materials. In an argon or nitrogen atmosphere, one of LiF or BN is mixed and ground with a sample to be tested to obtain The mixed powder with a particle size of 30-38 μm is molded, and the pressed sample is packaged in a double-mirror stainless steel plate with a through hole that is larger than the pressed sample and thicker than the pressed sample, and then sealed on the double-mirror surface. Pressed samples in stainless steel plates are stored in metal containers filled with argon or nitrogen. The invention ensures that the sample can be stored in a closed argon or nitrogen atmosphere without oxidation for a long time, and the surrounding rigid stainless steel metal plate also plays a good role in protecting the pressed sample block, so that it will not be damaged due to unexpected reasons. The pressed sample block cracks or breaks, which is conducive to long-distance delivery and carrying.

A method of producing a regenerated hydrotreating catalyst, including a first step of preparing a hydrotreating catalyst that has been used for hydrotreatment of a petroleum fraction and has a metal element selected from Group 6 elements of the periodic table; a second step of performing regeneration treatment for part of the catalyst prepared in the first step, then performing X-ray absorption fine structure analysis for the catalyst after the regeneration treatment, and obtaining regeneration treatment conditions in which a ratio IS / IO of a peak intensity IS of a peak attributed to a bond between the metal element and a sulfur atom to a peak intensity IO of a peak attributed to a bond between the metal element and an oxygen atom is in the range of 0.1 to 0.3 in a radial distribution curve obtained from an extended X-ray absorption fine structure spectrum.

The invention discloses a synchrotron radiation in-situ detection device for electrocatalytic reaction. It consists of a front ionization chamber, a rear ionization chamber (or a fluorescence detector) and an in situ cell of a synchrotron radiation X-ray absorption fine structure spectroscopy (XAFS) line station. By assembling the membrane electrode for the electrocatalytic reaction in the in-situ cell, under the condition that the detection windows of each component in the in-situ cell are on the same center line, X-rays are used to irradiate the membrane electrode, and the X-rays are transmitted or reflected. After arriving at the synchrotron radiation XAFS line station, the ionization chamber or fluorescence detector realizes the in-situ detection of the catalyst structure during the electrocatalytic reaction; the detection window of the in-situ cell is in the center of the flow field plate, and the dead volume is small, which improves the accuracy of the experimental data. Accuracy and reliability; the heating plate and the flow field plate in the in-situ cell are fixed together with screws, which not only realizes the sealing of the detection window on the flow field plate, but also facilitates the assembly and replacement of membrane electrodes. It is a set of detection devices suitable for studying the process and mechanism of electrocatalytic reactions.

The application discloses an intelligent electronic device, a QXAFS (quick X-ray absorption fine structure) system and a data acquisition and motor control method. The intelligent electronic device replaces a stepper motor controller and a scaler in a conventional XAFS (X-ray absorption fine structure) experimental system; and by employing a programmable device as a core component, the electronic device realizes analog acquisition via a multi-channel ADC acquisition circuit combining with a current amplifier in the quick XAFS system, or realizes integral form data acquisition by using the counting function of a programmable device combining a V / F converter on the quick XAFS system. The programmable device controls the stepper motor through reading a control curve configured in a RAM, while performs data acquisition in a control segment allowing the data acquisition, thus achieving a high-speed synchronization of the stepper motor and the data acquisition, and through sampling data in the stationary or slow control segment of the control curve, preventing energy movement in the process of data acquisition, and obtaining a best solution in the contradiction between a spectrum sweep speed and the energy movement.