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Peiping Zhu

Bio: Peiping Zhu is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Phase-contrast imaging & Grating. The author has an hindex of 20, co-authored 87 publications receiving 1268 citations. Previous affiliations of Peiping Zhu include University of Science and Technology of China.


Papers
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Journal ArticleDOI
TL;DR: Compared to the existing phase-stepping approach, the main advantages of this new method dubbed “reverse projection” are not only the significantly reduced delivered dose, without the degradation of the image quality, but also the much higher efficiency.
Abstract: Phase sensitive X-ray imaging methods can provide substantially increased contrast over conventional absorption-based imaging and therefore new and otherwise inaccessible information. The use of gratings as optical elements in hard X-ray phase imaging overcomes some of the problems that have impaired the wider use of phase contrast in X-ray radiography and tomography. So far, to separate the phase information from other contributions detected with a grating interferometer, a phase-stepping approach has been considered, which implies the acquisition of multiple radiographic projections. Here we present an innovative, highly sensitive X-ray tomographic phase-contrast imaging approach based on grating interferometry, which extracts the phase-contrast signal without the need of phase stepping. Compared to the existing phase-stepping approach, the main advantages of this new method dubbed "reverse projection" are not only the significantly reduced delivered dose, without the degradation of the image quality, but also the much higher efficiency. The new technique sets the prerequisites for future fast and low-dose phase-contrast imaging methods, fundamental for imaging biological specimens and in vivo studies.

216 citations

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TL;DR: In this article, a low cost and reliable hydrothermal method was developed for the tunable synthesis of flower-like and urchin-like zinc silicate nanostructures.
Abstract: A low cost and reliable hydrothermal method was developed for the tunable synthesis of flower-like and urchin-like zinc silicate nanostructures. High resolution TEM, XRD, solid state Si-29 NMR spectra and X-ray nanotomography revealed new morphologies and crystal structures. Solid state NMR indicated very different silicon bonding patterns between the two materials. For urchin-like zinc silicates, a synchrotron based three dimensional X-ray nanotomography technique provided unprecedented structural details and revealed structural defects during the assembly process. For flower-like zinc silicates, HRTEM images showed that their secondary nanopetals had a clay-like layered structure, resulting in a higher BET surface area of 236 m(2) g(-1) as well as higher adsorption capacity for lead ions at 210 mg g(-1) than reported zinc silicate samples. The adsorption isotherms and mechanism were investigated.

80 citations

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TL;DR: A full-field transmission X-ray microscope operating continuously from 5 keV to 12 keV with fluorescence mapping capability has been designed and constructed at the Beijing Synchrotron Radiation Facility and the optics design, testing of spatial resolution and fluorescence sensitivity are presented.
Abstract: A full-field transmission X-ray microscope (TXM) operating continuously from 5 keV to 12 keV with fluorescence mapping capability has been designed and constructed at the Beijing Synchrotron Radiation Facility, a first-generation synchrotron radiation facility operating at 2.5 GeV. Spatial resolution better than 30 nm has been demonstrated using a Siemens star pattern in both absorption mode and Zernike phase-contrast mode. A scanning-probe mode fluorescence mapping capability integrated with the TXM has been shown to provide 50 p. p. m. sensitivity for trace elements with a spatial resolution (limited by probing beam spot size) of 20 mm. The optics design, testing of spatial resolution and fluorescence sensitivity are presented here, including performance measurement results.

79 citations

Journal ArticleDOI
TL;DR: In this paper, the application of the conventional CT reconstruction algorithm is not always satisfactory for the new diffractionenhanced imaging (DEI-CT) imaging and a new mathematical framework for imaging reconstruction is presented.
Abstract: Recently taking advantage of the novel diffraction-enhanced imaging (DEI) method, one very effective and practical phase contrast imaging technique—a new x-ray computed tomography scheme based on DEI (DEI-CT) showed promising results, really superior to those of conventional CT imaging. In this letter, we show that the application of the conventional CT reconstruction algorithm is not always satisfactory for the new DEI-CT imaging and a new mathematical framework for imaging reconstruction is presented. Experimental data collected at the Beijing synchrotron radiation facility are also discussed using the new algorithm.

76 citations

Journal ArticleDOI
TL;DR: In this article, a direct reconstruction algorithm for directional-derivative projections of computed tomography of diffraction enhanced imaging is proposed, which does not require any restoration processing compared with the current two-step methods.
Abstract: X-ray diffraction enhanced imaging based on synchrotron radiation has extremely high sensitivity of weakly absorbing low-Z samples in medical and biological fields. This letter is dedicated to a direct reconstruction algorithm for directional-derivative projections of computed tomography of diffraction enhanced imaging. It is a “one-step” algorithm and does not require any restoration processing compared with the current “two-step” methods. The actual values of the sample’s refractive index decrement can be estimated from its reconstruction images directly. The algorithm is proven by the actual experiment at the Beijing Synchrotron Radiation Facility and the reconstructed images are described finally.

76 citations


Cited by
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Journal Article
TL;DR: In this article, a fast Fourier transform method of topography and interferometry is proposed to discriminate between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour generation techniques.
Abstract: A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

3,742 citations

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TL;DR: In this review, recent developments on nanostructured sulfur cathodes and mechanisms behind their operation are presented and discussed and progress on novel characterization of sulfurCathodes is summarized, as it has deepened the understanding of sulfur cathode and will guide further rational design of sulfur electrodes.
Abstract: Rechargeable Li/S batteries have attracted significant attention lately due to their high specific energy and low cost. They are promising candidates for applications, including portable electronics, electric vehicles and grid-level energy storage. However, poor cycle life and low power capability are major technical obstacles. Various nanostructured sulfur cathodes have been developed to address these issues, as they provide greater resistance to pulverization, faster reaction kinetics and better trapping of soluble polysulfides. In this review, recent developments on nanostructured sulfur cathodes and mechanisms behind their operation are presented and discussed. Moreover, progress on novel characterization of sulfur cathodes is also summarized, as it has deepened the understanding of sulfur cathodes and will guide further rational design of sulfur electrodes.

1,727 citations

Journal Article
TL;DR: In this article, a self-scanned 1024 element photodiode array and a minicomputer are used to measure the phase (wavefront) in the interference pattern of an interferometer to lambda/100.
Abstract: A self-scanned 1024 element photodiode array and minicomputer are used to measure the phase (wavefront) in the interference pattern of an interferometer to lambda/100. The photodiode array samples intensities over a 32 x 32 matrix in the interference pattern as the length of the reference arm is varied piezoelectrically. Using these data the minicomputer synchronously detects the phase at each of the 1024 points by a Fourier series method and displays the wavefront in contour and perspective plot on a storage oscilloscope in less than 1 min (Bruning et al. Paper WE16, OSA Annual Meeting, Oct. 1972). The array of intensities is sampled and averaged many times in a random fashion so that the effects of air turbulence, vibrations, and thermal drifts are minimized. Very significant is the fact that wavefront errors in the interferometer are easily determined and may be automatically subtracted from current or subsequent wavefrots. Various programs supporting the measurement system include software for determining the aperture boundary, sum and difference of wavefronts, removal or insertion of tilt and focus errors, and routines for spatial manipulation of wavefronts. FFT programs transform wavefront data into point spread function and modulus and phase of the optical transfer function of lenses. Display programs plot these functions in contour and perspective. The system has been designed to optimize the collection of data to give higher than usual accuracy in measuring the individual elements and final performance of assembled diffraction limited optical systems, and furthermore, the short loop time of a few minutes makes the system an attractive alternative to constraints imposed by test glasses in the optical shop.

1,300 citations

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TL;DR: An overview of the main theoretical and experimental developments and of the important steps performed towards the clinical implementation of phase-contrast x-ray imaging is given.
Abstract: Phase-contrast x-ray imaging (PCI) is an innovative method that is sensitive to the refraction of the x-rays in matter. PCI is particularly adapted to visualize weakly absorbing details like those often encountered in biology and medicine. In past years, PCI has become one of the most used imaging methods in laboratory and preclinical studies: its unique characteristics allow high contrast 3D visualization of thick and complex samples even at high spatial resolution. Applications have covered a wide range of pathologies and organs, and are more and more often performed in vivo. Several techniques are now available to exploit and visualize the phase-contrast: propagation- and analyzer-based, crystal and grating interferometry and non-interferometric methods like the coded aperture. In this review, covering the last five years, we will give an overview of the main theoretical and experimental developments and of the important steps performed towards the clinical implementation of PCI.

796 citations

Journal ArticleDOI
TL;DR: In this contribution, the technical bases of IR are reviewed and the currently available algorithms released by the major CT manufacturers are described and the current status of their clinical implementation is surveyed.
Abstract: The current evidence on the clinical implementation of iterative reconstruction into CT protocols shows substantial promise for major improvements in image quality, chiefly noise reduction—with subsequent radiation dose reduction—and artifact suppression.

521 citations