scholarly journals Investigation on the role of the dielectric loss in metamaterial absorber

2010 ◽  
Vol 18 (7) ◽  
pp. 6598 ◽  
Author(s):  
ChengGang Hu ◽  
Xiong Li ◽  
Qin Feng ◽  
Xu’Nan Chen ◽  
XianGang Luo
Keyword(s):  
Dielectric Loss ◽  
Metamaterial Absorber

The Dielectric Loss of Single Crystal and Polycrystalline TiO2

1997 ◽  
Vol 500 ◽  
Author(s):  
Xiaoru Wang ◽  
Alan Templeton ◽  
Stuart J. Penn ◽  
Neil McN. Alford
Keyword(s):  
Dielectric Loss ◽  
Single Crystal ◽  
Mixed Valence ◽  
Dielectric Materials ◽  
Oxygen Stoichiometry ◽  
Ion Conductor ◽  
Microwave Dielectric ◽  
Valence States ◽  
Oxygen Ion Conductor

ABSTRACTThe dielectric loss of single crystal and polycrystalline TiO2 has been studied. In polycrystalline TiO2 the dielectric loss is determined by both the microstructure and by the oxygen stoichiometry. Experiments have been carried out to determine the influence of both the microstructure (particularly porosity) and the oxygen stoichiometry. The TiO2 powder has been doped with partially stabilised zirconia, an oxygen ion conductor, in order to modify the oxygen stoichiometry. Sintered discs have been examined for loss as a function zirconia doping, pore volume and as a function of temperature. The behaviour of the doped and undoped titania powders is significantly different. Since many microwave dielectric materials contain Ti eg Ba-Ti-O, Ba-Nd-Ti-O, (Ba-RE-Ti-O, RE=Rare Earth), Zr-Sn-Ti-O etc it is essential to understand the role of the titanium, particularly as it can exist in mixed valence states, and the role of oxygen and its influence on the dielectric loss.

The utilization of time-resolved dielectric loss to probe the role of the surface in heterogeneous photochemistry

1986 ◽  
Vol 82 (12) ◽  
pp. 3625 ◽  
Author(s):  
Christopher J. Dobbin ◽  
Alan R. McIntosh ◽  
James R. Bolton ◽  
Zoran D. Popovic ◽  
John R. Harbour
Keyword(s):  
Dielectric Loss ◽  
Time Resolved

Carbon-Induced UV Sensitivity in Aluminum Nitride

1998 ◽  
Vol 4 (S2) ◽  
pp. 570-571
Author(s):  
Y. Berta ◽  
R. A. Gerhardt
Keyword(s):  
Dielectric Loss ◽  
Aluminum Nitride ◽  
Uv Irradiation ◽  
High Performance ◽  
High Energy ◽  
Multichip Modules ◽  
Low Oxygen ◽  
Carbon Impurities ◽  
Ultimate Purpose

Aluminum nitride, translucent, calcia-sintered and hot pressed, with its superior thermal properties has applications in high performance electronic devices such as multichip modules. In these applications, A1N is exposed to high energy electromagnetic sources which could alter its properties; for example, upon UV irradiation, thermal conductivity drops and dielectric loss increases. These observations indicate that the UV altered properties are due to the presence of impurities. The early studies concentrated primarily on oxygen doped samples, which photodarken upon UV exposure; the role of other impurities was not considered.In the current work, we consider the role of carbon in the microstructure of two very low oxygen content (< 0.3 wt %), carbon-containing samples, labeled B and E, for the ultimate purpose of 3 determining the mechanism by which carbon impurities affect the properties of A1N. Previous work on these samples correlated higher carbon content with a lower increase in the dielectric loss factor, after UV irradiation,

The Role of Glassy Grain Boundary Phases in the Microwave Joining of Alumina

1994 ◽  
Vol 347 ◽  
Author(s):  
Pamela Davis ◽  
Jon Binner ◽  
Tom Cross ◽  
John Fernie
Keyword(s):  
Dielectric Loss ◽  
Grain Boundary ◽  
Resonant Cavity ◽  
Single Mode ◽  
Alumina Ceramic ◽  
Boundary Phase ◽  
Alumina Ceramics ◽  
Axial Pressure ◽  
Individual Grains

ABSTRACTThe role of intergranular glassy phases in the microwave joining of alumina ceramic rods has been investigated. Alumina ceramics of different purities have been examined using a TE102 single mode rectangular resonant cavity operating at 2.45 GHz. Temperature and axial pressure were varied and the resultant join microstructures analyzed. The presence of a glassy grain boundary phase has been shown to improve the ability to microwave join alumina ceramics by increasing the dielectric loss of the ceramic and, when softened, by enabling the alumina grains to flow under the imposed load. Evidence has also been found for the sintering of individual grains where they have come into contact across the join line.

Role of dactinomycin in the improved survival of children with Wilms' tumor

JAMA ◽  
1966 ◽  
Vol 195 (12) ◽  
pp. 1005-1009 ◽  
Author(s):  
D. J. Fernbach
Keyword(s):  
Wilms Tumor

Role of the allergist in diagnosis and management of patients with uveitis

JAMA ◽  
1966 ◽  
Vol 195 (3) ◽  
pp. 167-172 ◽  
Author(s):  
T. E. Van Metre
Keyword(s):  
Diagnosis And Management
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