scholarly journals Effects of Interfacial Charge on the DC Dielectric Properties of Nanocomposites

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Jiaming Yang ◽  
Congji Liu ◽  
Changji Zheng ◽  
Hong Zhao ◽  
Xuan Wang ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Breakdown Strength ◽  
Interface Layer ◽  
Low Density Polyethylene ◽  
X Ray ◽  
X Ray Scattering ◽  
Scattering Effects ◽  
Dielectric Performance ◽  
Positive Effect ◽  
Interfacial Charge

The interfacial charge phenomenon of MgO/low-density polyethylene (LDPE) and SiO2/LDPE nanocomposites was measured by synchrotron radiation small-angle X-ray scattering. Based on the Porod theory, the Porod curve of SiO2/LDPE nanocomposite shows negative divergence but the LDPE and MgO/LDPE do not, which reveals that interfacial charge may exist in the SiO2/LDPE nanocomposite. The DC dielectric properties of the nanocomposites are closely related to the interfacial charge. Experimental results show that the SiO2/LDPE nanocomposite has lower DC conductivity, less space charge, and higher DC breakdown strength than the MgO/LDPE nanocomposite. It is thought that the interfacial charge has a positive effect on the DC dielectric performance of nanocomposites, and the mechanism could be attributed to the scattering effects of the interfacial charge on the carrier migration. There is no obvious interfacial charge in the MgO/LDPE nanocomposite, but it still has excellent DC dielectric properties compared with LDPE, which indicates that the interfacial charge is not the only factor affecting the dielectric properties; the dipole interface layer and the reduction of free volume can also inhibit the migration of carriers and decrease electrons free path, improving the dielectric performance.

X-ray scattering effects of ionic size in solid solutions KCl–KBr

1970 ◽  
Vol 3 (5) ◽  
pp. 385-388 ◽  
Author(s):  
P. Luova ◽  
P. Tuominen ◽  
P. Vanha-Kämppä
Keyword(s):  
Solid Solutions ◽  
X Ray ◽  
X Ray Scattering ◽  
Scattering Effects ◽  
Ionic Size ◽  
Ray Scattering

A feasibility study of time of flight cone beam computed tomography imaging

2021 ◽  
pp. 1-14
Author(s):  
Ignacio O. Romero ◽  
Changqing Li
Keyword(s):  
Computed Tomography ◽  
Cone Beam Computed Tomography ◽  
Time Of Flight ◽  
Cone Beam ◽  
X Ray ◽  
X Ray Scattering ◽  
Scattering Effects ◽  
Breast Phantom ◽  
Scatter Reduction ◽  
Strong Scattering

BACKGROUND: The time of flight (TOF) cone beam computed tomography (CBCT) was recently shown to reduce the X-ray scattering effects by 95%and improve the image CNR by 110%for large volume objects. The advancements in X-ray sources like in compact Free Electron Lasers (FEL) and advancements in detector technology show potential for the TOF method to be feasible in CBCT when imaging large objects. OBJECTIVE: To investigate feasibility and efficacy of TOF CBCT in imaging smaller objects with different targets such as bones and tumors embedded inside the background. METHODS: The TOF method used in this work was verified using a 24cm phantom. Then, the GATE software was used to simulate the CBCT imaging of an 8 cm diameter cylindrical water phantom with two bone targets using a modeled 20 keV quasi-energetic FEL source and various TOF resolutions ranging from 1 to 1000 ps. An inhomogeneous breast phantom of similar size with tumor targets was also imaged using the same system setup. RESULTS: The same results were obtained in the 24cm phantom, which validated the applied CBCT simulation approach. For the case of 8cm cylindrical phantom and bone target, a TOF resolution of 10 ps improved the image contrast-to-noise ratio (CNR) by 57%and reduced the scatter-to-primary ratio (SPR) by 8.63. For the case of breast phantom and tumor target, image CNR was enhanced by 12%and SPR was reduced by 1.35 at 5 ps temporal resolution. CONCLUSIONS: This study indicates that a TOF resolution below 10 ps is required to observe notable enhancements in the image quality and scatter reduction for small objects around 8cm in diameter. The strong scattering targets such as bone can result in substantial improvements by using TOF CBCT.

scholarly journals Structural characterization using the multiple scattering effects in grazing-incidence small-angle X-ray scattering

2008 ◽  
Vol 41 (1) ◽  
pp. 134-142 ◽  
Author(s):  
Byeongdu Lee ◽  
Chieh-Tsung Lo ◽  
P. Thiyagarajan ◽  
Dong R. Lee ◽  
Zhongwei Niu ◽  
...  
Keyword(s):  
Multiple Scattering ◽  
Small Angle ◽  
Incident Angle ◽  
Average Distance ◽  
Grazing Incidence ◽  
X Ray ◽  
X Ray Scattering ◽  
Scattering Effects ◽  
Multiple Scattering Effects ◽  
Ray Scattering

The multiple scattering effects present in grazing-incidence small-angle X-ray scattering (GISAXS) data and interference between them are addressed theoretically as well as experimentally with measurement of a series of patterns at different incident angles, referred to as `incident-angle-resolved GISAXS' (IAR-GISAXS). X-ray reflectivity (XR), GISAXS and IAR-GISAXS of virus particles on Si-substrate supported-polystyrene films have been measured and all the data have been analyzed with appropriate formalisms. It was found that under certain conditions it is possible to extract the correct structural features of the materials from the GISAXS/IAR-GISAXS data using the kinematic SAXS formalisms, without the need to use the distorted-wave Born approximation. Furthermore, the Kiessig fringes in GISAXS enable the measurement of the average distance between the particle and the substrate, similar to the measurement of film thickness using the fringes in the XR data. It is believed that the methods developed here will expand the application of GISAXS as they enable the application of model-independent and kinematic SAXS theories to nanostructured two-dimensional ordered films.

scholarly journals X-ray structure of barium titanate – missed opportunities

2000 ◽  
Vol 56 (5) ◽  
pp. 918-919
Author(s):  
K. S. Chandrasekaran ◽  
S. K. Mohanlal ◽  
R. Saravanan ◽  
S. Israel
Keyword(s):  
Barium Titanate ◽  
Symmetric Space ◽  
X Ray Diffraction ◽  
Missed Opportunities ◽  
X Ray ◽  
Atomic Displacements ◽  
Polar Crystal ◽  
X Ray Scattering ◽  
Scattering Effects ◽  
Ferroelectric Structure

Anomalous X-ray scattering effects are quite extensive in the noncentrosymmetric ferroelectric structure of barium titanate, and typical estimates for three published X-ray diffraction experiments are computed. These data show that the Bijvoet pairs should not be averaged before least-squares refinement for this polar crystal with small atomic displacements from a higher symmetric space group.

X-ray Diffraction from Surfaces and Interfaces:Atomic Structure and Morphology

1990 ◽  
Vol 208 ◽  
Author(s):  
E. Vlieg ◽  
I. K. Robinsson ◽  
J. F Van Der Veen
Keyword(s):  
Surface Science ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure And Morphology ◽  
X Ray Scattering ◽  
Scattering Effects ◽  
Radiation Sources ◽  
Surface Disorder ◽  
Multiple Scattering Effects ◽  
Ray Scattering

ABSTRACTThe emergence of synchrotron radiation sources has greatly stimulated the use of X-ray scattering in surface science. The absence of multiple-scattering effects allows a straightforward data analysis. In addition to determining geometric structures, it is also possible with X-ray scattering to obtain information on various types of surface disorder. The large penetration depth enables the investigation of interfaces.

Small- and wide-angle X-ray scattering characterization of 1-hexene linear low-density polyethylene

1995 ◽  
Vol 196 (8) ◽  
pp. 2537-2544 ◽  
Author(s):  
Antonio Marigo ◽  
Gianmatteo Cingano ◽  
Carla Marega ◽  
Roberto Zannetti ◽  
Giuseppe Ferrara ◽  
...  
Keyword(s):  
Low Density Polyethylene ◽  
Low Density ◽  
Wide Angle ◽  
Linear Low Density Polyethylene ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

X-Ray Scattering Effects Due to Localized Static Lattice Defects

1955 ◽  
Vol 99 (6) ◽  
pp. 1777-1781 ◽  
Author(s):  
Charles W. Tucker ◽  
Peter Senio
Keyword(s):  
Lattice Defects ◽  
X Ray ◽  
X Ray Scattering ◽  
Scattering Effects ◽  
Static Lattice ◽  
Ray Scattering
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