Faculty Opinions recommendation of Beam heating from a fourth-generation synchrotron source.

Technological advancements in X-ray imaging using bright and coherent synchrotron sources now allows to decouple sample size and resolution, while maintaining high sensitivity to the microstructure of soft, partially dehydrated tissues. The recently developed imaging technique, hierarchical phase-contrast tomography, is a comprehensive approach to address the challenge of organ-scale (up to tens of centimeters) soft tissue imaging with resolution and sensitivity down to the cellular level. Using this technique, we imaged ex vivo an entire human left lung at an isotropic voxel size of 25.08 μm along with local zooms down to 6.05 - 6.5 μm and 2.45 - 2.5 μm in voxel size. The high tissue contrast offered by the fourth-generation synchrotron source at the European Synchrotron Radiation Facility reveals complex multiscale anatomical constitution of the human lung from the macroscopic (centimeter) down to the microscopic (micrometer) scale. The dataset provides complete organ-scale 3D information of the secondary pulmonary lobules and delineates the microstructure of lung nodules with unprecedented detail.

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Compact laser accelerators for X-ray phase-contrast imaging

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2013.0032 ◽

2014 ◽

Vol 372 (2010) ◽

pp. 20130032 ◽

Cited By ~ 23

Author(s):

Z. Najmudin ◽

S. Kneip ◽

M. S. Bloom ◽

S. P. D. Mangles ◽

O. Chekhlov ◽

...

Keyword(s):

Generation X ◽

Phase Contrast ◽

Electron Beams ◽

Imaging Techniques ◽

Phase Contrast Imaging ◽

Fourth Generation ◽

Light Sources ◽

Contrast Imaging ◽

Synchrotron Source ◽

X Ray

Advances in X-ray imaging techniques have been driven by advances in novel X-ray sources. The latest fourth-generation X-ray sources can boast large photon fluxes at unprecedented brightness. However, the large size of these facilities means that these sources are not available for everyday applications. With advances in laser plasma acceleration, electron beams can now be generated at energies comparable to those used in light sources, but in university-sized laboratories. By making use of the strong transverse focusing of plasma accelerators, bright sources of betatron radiation have been produced. Here, we demonstrate phase-contrast imaging of a biological sample for the first time by radiation generated by GeV electron beams produced by a laser accelerator. The work was performed using a greater than 300 TW laser, which allowed the energy of the synchrotron source to be extended to the 10–100 keV range.

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Observations on the Structure of Ta2O5

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100095959 ◽

1972 ◽

Vol 30 ◽

pp. 540-541

Author(s):

P. S. Kotval ◽

C. J. Dewit

Keyword(s):

Electron Microscope ◽

Structural Features ◽

Amorphous Structure ◽

Polished Surface ◽

Distilled Water ◽

Anodic Films ◽

Amorphous Films ◽

Beam Heating ◽

Diffraction Patterns ◽

Hexagonal Arrays

The structure of Ta2O5 has been described in the literature in several different crystallographic forms with varying unit cell lattice parameters. Earlier studies on films of Ta2O5 produced by anodization of tantalum have revealed structural features which are not consistent with the parameters of “bulk” Ta2O5 crystalsFilms of Ta2O5 were prepared by anodizing a well-polished surface of pure tantalum sheet. The anodic films were floated off in distilled water, collected on grids, dried and directly examined in the electron microscope. In all cases the films were found to exhibit diffraction patterns representative of an amorphous structure. Using beam heating in the electron microscope, recrystallization of the amorphous films can be accomplished as shown in Fig. 1. As suggested by earlier work, the recrystallized regions exhibit diffraction patterns which consist of hexagonal arrays of main spots together with subsidiary rows of super lattice spots which develop as recrystallization progresses (Figs. 2a and b).

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Fission Gas Bubbles in Fractured UO2

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101177 ◽

1968 ◽

Vol 26 ◽

pp. 286-287

Author(s):

O. M. Katz

Keyword(s):

Electron Microscopy ◽

Thermal Gradient ◽

Gas Bubbles ◽

Inert Gas ◽

Thermal Gradients ◽

Fission Gas ◽

Beam Heating ◽

Limited Application ◽

Bubble Characteristics ◽

Electron Beam Heating

The swelling of irradiated UO2 has been attributed to the migration and agglomeration of fission gas bubbles in a thermal gradient. High temperatures and thermal gradients obtained by electron beam heating simulate reactor behavior and lead to the postulation of swelling mechanisms. Although electron microscopy studies have been reported on UO2, two experimental procedures have limited application of the results: irradiation was achieved either with a stream of inert gas ions without fission or at depletions less than 2 x 1020 fissions/cm3 (∼3/4 at % burnup). This study was not limited either of these conditions and reports on the bubble characteristics observed by transmission and fractographic electron microscopy in high density (96% theoretical) UO2 irradiated between 3.5 and 31.3 x 1020 fissions/cm3 at temperatures below l600°F. Preliminary results from replicas of the as-polished and etched surfaces of these samples were published.

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X-Ray absorption edge elemental imaging of B. thuringienis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100153038 ◽

1989 ◽

Vol 47 ◽

pp. 212-213

Author(s):

R. L. Stears

Keyword(s):

Absorption Edge ◽

Elemental Distribution ◽

X Rays ◽

Differential Absorption ◽

Synchrotron Source ◽

High Brightness ◽

X Ray ◽

Elemental Imaging ◽

Cellular Integrity ◽

X Ray Absorption

Because of the nature of the bacterial endospore, little work has been done on analyzing their elemental distribution and composition in the intact, living, hydrated state. The majority of the qualitative analysis entailed intensive disruption and processing of the endospores, which effects their cellular integrity and composition.Absorption edge imaging permits elemental analysis of hydrated, unstained specimens at high resolution. By taking advantage of differential absorption of x-ray photons in regions of varying elemental composition, and using a high brightness, tuneable synchrotron source to obtain monochromatic x-rays, contact x-ray micrographs can be made of unfixed, intact endospores that reveal sites of elemental localization. This study presents new data demonstrating the application of x-ray absorption edge imaging to produce elemental information about nitrogen (N) and calcium (Ca) localization using Bacillus thuringiensis as the test specimen.

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TEM study of buried cobalt disilicide layers formed by ion implantation: Identification of cobalt monosilicide inclusions

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100176010 ◽

1990 ◽

Vol 48 (4) ◽

pp. 576-577

Author(s):

A. De Veirman ◽

J. Van Landuyt ◽

K.J. Reeson ◽

R. Gwilliam ◽

C. Jeynes ◽

...

Keyword(s):

Ion Implantation ◽

Annealing Treatment ◽

Silicon On Insulator ◽

High Dose ◽

Nitrogen Flow ◽

Cobalt Disilicide ◽

Transmission Electron ◽

Beam Heating ◽

Co Concentration ◽

Silicon On Insulator Technology

In analogy to the formation of SIMOX (Separation by IMplanted OXygen) material which is presently the most promising silicon-on-insulator technology, high-dose ion implantation of cobalt in silicon is used to synthesise buried CoSi2 layers. So far, for high-dose ion implantation of Co in Si, only formation of CoSi2 is reported. In this paper it will be shown that CoSi inclusions occur when the stoichiometric Co concentration is exceeded at the peak of the Co distribution. 350 keV Co+ ions are implanted into (001) Si wafers to doses of 2, 4 and 7×l017 per cm2. During the implantation the wafer is kept at ≈ 550°C, using beam heating. The subsequent annealing treatment was performed in a conventional nitrogen flow furnace at 1000°C for 5 to 30 minutes (FA) or in a dual graphite strip annealer where isochronal 5s anneals at temperatures between 800°C and 1200°C (RTA) were performed. The implanted samples have been studied by means of Rutherford Backscattering Spectroscopy (RBS) and cross-section Transmission Electron Microscopy (XTEM).

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Texture of submicron Ni-Mn-Ga films studied by X-ray diffraction at the ANKA synchrotron source

Zeitschrift für Kristallographie ◽

10.1524/zkri.2007.2007.suppl_26.229 ◽

2007 ◽

Vol 2007 (suppl_26) ◽

pp. 229-234 ◽

Cited By ~ 1

Author(s):

V. A. Chernenko ◽

S. Doyle ◽

M. Kohl ◽

P. Müllner ◽

S. Besseghini ◽

...

Keyword(s):

X Ray Diffraction ◽

Synchrotron Source ◽

X Ray

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COORDINATED DISTRIBUTED SCHEDULING IN WIRELESS MESH NETWORK

INTERNATIONAL JOURNAL OF COMPUTERS & TECHNOLOGY ◽

10.24297/ijct.v3i3a.2940 ◽

2012 ◽

Vol 3 (3) ◽

pp. 368-374

Author(s):

Usha Kumari ◽

Udai Shankar

Keyword(s):

Network Performance ◽

Mesh Networks ◽

Mac Protocol ◽

Scheduling Algorithm ◽

Ieee 802.16 ◽

Distributed Scheduling ◽

Mesh Network ◽

Fourth Generation ◽

Network Nodes ◽

Wireless Mesh

IEEE 802.16 based wireless mesh networks (WMNs) are a promising broadband access solution to support flexibility, cost effectiveness and fast deployment of the fourth generation infrastructure based wireless networks. Reducing the time for channel establishment is critical for low latency/interactive Applications. According to IEEE 802.16 MAC protocol, there are three scheduling algorithms for assigning TDMA slots to each network node: centralized and distributed the distributed is further divided into two operational modes coordinated distributed and uncoordinated distributed. In coordinated distributed scheduling algorithm, network nodes have to transmit scheduling message in order to inform other nodes about their transfer schedule. In this paper a new approach is proposed to improve coordinated distributed scheduling efficiency in IEEE 802.16 mesh mode, with respect to three parameter Throughput, Average end to end delay and Normalized Overhead. For evaluating the proposed networks efficiency, several extensive simulations are performed in various network configurations and the most important system parameters which affect the network performance are analyzed

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