Zhiguo Liu

Characterization of polycapillary X-ray lens for application in confocal three-dimensional energy-dispersive micro X-ray diffraction experiments

A confocal technology based on polycapillary X-ray optics is proposed to perform three-dimensional energy-dispersive micro X-ray diffraction. A three-dimensional energy-dispersive micro X-ray diffractometer based on a polycapillary focusing X-ray lens (PFXRL) in the excitation channel and a polycapillary parallel X-ray lens (PPXRL) in the detection channel has been designed. At 2theta = 90^ circ, the lateral resolution l_X times l_Y of this diffractometer is 49.7xa0times 49.9u2005rm micro m at 7.5u2005keV, and its depth resolution d_Z is 48.1u2005rm micro m at 8.0u2005keV. The total resolution of this diffractometer in Delta d/d is 6.5% at 6.4u2005keV and 2theta = 140.2^ circ.

Focusing synchrotron radiation using a polycapillary half-focusing X-ray lens for imaging.

An imaging system based on a polycapillary half-focusing X-ray lens (PHFXRL) and synchrotron radiation source has been designed. The focal spot size and the gain in power density of the PHFXRL were 22 microm (FWHM) and 4648, respectively, at 14.0 keV. The spatial resolution of this new imaging system was better than 5 microm when an X-ray charge coupled device with a pixel size of 10.9 x 10.9 microm was used. A fossil of an ancient biological specimen was imaged using this system.

Performance of polycapillary X-ray optics for confocal energy-dispersive small-angle X-ray scattering

A confocal energy-dispersive small-angle X-ray scattering (EDSAXS) setup based on polycapillary optics was designed. In this confocal EDSAXS setup, a polycapillary slightly focusing X-ray lens (PSFXRL) and a polycapillary parallel X-ray lens (PPXRL) with a long input focal distance were placed confocally in the excitation channel and detection channel, respectively. This confocal configuration was helpful in improving the signal-to-noise ratio of the EDSAXS. The high gain in power density of the PSFXRL and PPXRL decreased the power requirement of the X-ray source for EDSAXS. The confocal EDSAXS technology could be used to perform nondestructive and in situ analysis of samples such as milk powder in its packaging.

Application of confocal X-ray fluorescence micro-spectroscopy to the investigation of paint layers

A confocal micro X-ray fluorescence (MXRF) spectrometer based on polycapillary X-ray optics was used for the identification of paint layers. The performance of the confocal MXRF was studied. Multilayered paint fragments of a car were analyzed nondestructively to demonstrate that this confocal MXRF instrument could be used in the discrimination of the various layers in multilayer paint systems.

Millimeter-wave imaging with slab focusing lens made of electromagnetic-induction materials.

A slab focusing lens in this work has been designed, which consists of electromagnetic-induction materials (cage-shaped granules of conductor materials) and polymethyl methacrylate (PMMA) materials. A compound lens with a thickness of 32 mm is composed of two slab focusing lenses, and has a refractive index of 1.41 at 35 GHz. Millimeter-wave (MMW) images of metallic objects have been obtained with the compound lens. The image quality has been compared by means of the compound lens and the polyethylene lens. The experimental results show good feasibility of the compound lens in MMW imaging.

Property of slice square polycapillary x-ray optics

A geometrical description of square polycapillary x-ray optics and the basic theory of the transmission of x-rays are presented. A method of numerical calculation is developed based on ray-tracing theory. The method simulates the intensity distribution of x-rays propagating through slice square polycapillary x-ray optics. The simulation results are compared with the experimental results.

Vibration Sensor Approaches for the Monitoring of Sand Production in Bohai Bay

The real-time monitoring of sand production has always been an important issue during the process of oil production in offshore field. This paper illustrates a new alternative vibration sensor approach to monitor the sand production. A special broadband sensor was selected. Then the time-frequency analysis, characteristic sand frequency band filter method, and peak searching-denoising method were proposed to enhance the detection ability of sand vibration signals in strong background noises of crude oil flow. After that, visible differences in time-frequency domain and power spectrum between sand and nonsand production well can be observed. Four typical wells in Bohai oil production platform were selected to investigate the monitoring effects of sand production. The monitoring findings show that there exists a good correlation between the vibration power spectrum amplitude and the sand production volume, which is consistent with actual results.

Confocal total reflection X-ray fluorescence technology based on an elliptical monocapillary and a parallel polycapillary X-ray optics

A total reflection X-ray fluorescence (TXRF) spectrometer based on an elliptical monocapillary X-ray lens (MXRL) and a parallel polycapillary X-ray lens (PPXRL) was designed. This TXRF instrument has micro focal spot, low divergence and high intensity of incident X-ray beam. The diameter of the focal spot of MXRL was 16.5u202fµm, and the divergence of the incident X-ray beam was 3.4u202fmrad. We applied this TXRF instrument to the micro analysis of a single-layer film containing Ni deposited on a Si substrate by metal vapor vacuum arc ion source.

The Three-Dimensional Elemental Distribution of 3D Printing Stainless Steel Gear via Confocal 3D–XRF Analysis

The macroscopic mechanical properties of 3D printing product are closely related to their microstructure, it has significant importance to accurately characterize the micro-structure of 3D printing products. Confocal three-dimensional micro-X-ray fluorescence (3D-XRF) is a good surface analysis technology widely used to analyse elements and elemental distributions. Therefore, this technique is also very suitable for element distribution measurement of 3D printing product which is printed layer by layer. In this paper the 3D-XRF technique was used to study the spatial elemental distribution of a micro zone from the 3D printing stainless steel gear. An elemental mapping of two orthogonal sections in the depth direction and three dimensional elemental rendering of one micro-region were obtained. The result shows that elemental distribution of the sample is not uniform, the elemental layer structure is formed in the depth direction, the content of the element in measured area vary smoothly, and with no elemental mutation region. This indicates that the 3D printing sample are fused well between layers and layers, with no large pores or bubbles inside the sample. This study demonstrates that it is feasible to make assessment for micro-structure of 3D printing metal product by using confocal 3D-XRF.

Millimeter wave imaging with electromagnetic-induction materials focusing lenses

The focusing device comprising two element focusing lenses made of electromagnetic-induction materials has been used in the active millimeter-wave (AMMW) imaging system. The electromagnetic-induction materials exhibit a refractive index of 1.502 at 35 GHz. The AMMW imaging system presented in this paper consists of an illumination source, a focusing device, a one dimensional receiver and a signal processing system. The MMW images of the metal strips and the concealed metal strips have been obtained. The experimental results show that the AMMM imaging system can detect the metal strips with and without the woolen cloth.