scholarly journals Some electrical properties of foreign and domestic micas and the effect of elevated temperatures on micas

1931 ◽  
Vol 7 (2) ◽  
pp. 403 ◽  
Author(s):  
A.B. Lewis ◽  
E.L. Hall ◽  
F.R. Caldwell
Keyword(s):  
Electrical Properties ◽  
Elevated Temperatures

scholarly journals Temperature Dependence of Mechanical, Electrical Properties and Crystal Structure of Polyethylene Blends for Cable Insulation

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1922 ◽  
Author(s):  
Lunzhi Li ◽  
Lisheng Zhong ◽  
Kai Zhang ◽  
Jinghui Gao ◽  
Man Xu
Keyword(s):  
High Temperature ◽  
Electrical Properties ◽  
Temperature Dependence ◽  
Elevated Temperatures ◽  
Breakdown Strength ◽  
Temperature Stability ◽  
Xrd Analysis ◽  
Insulation Material ◽  
Cable Insulation ◽  
Polyethylene Blends

There is a long-standing puzzle concerning whether polyethylene blends are a suitable substitution for cable-insulation-used crosslinking polyethylene (XLPE) especially at elevated temperatures. In this paper, we investigate temperature dependence of mechanical, electrical properties of blends with 70 wt % linear low density polyethylene (LLDPE) and 30 wt % high density polyethylene (HDPE) (abbreviated as 70 L-30 H). Our results show that the dielectric loss of 70 L-30 H is about an order of magnitude lower than XLPE, and the AC breakdown strength is 22% higher than XLPE at 90 °C. Moreover, the dynamic mechanical thermal analysis (DMA) measurement and hot set tests suggest that the blends shows optimal mechanical properties especially at high temperature with considerable temperature stability. Further scanning electron microscope (SEM) observation and X-ray diffraction (XRD) analysis uncover the reason for the excellent high temperature performance and temperature stability, which can be ascribed to the uniform fine-spherulite structure in 70 L-30 H blends with high crystallinity sustaining at high temperature. Therefore, our findings may enable the potential application of the blends as cable insulation material with higher thermal-endurance ability.

scholarly journals The effect of oxidation on structural and electrical properties of single wall carbon nanotubes

2011 ◽  
Vol 65 (4) ◽  
pp. 363-370 ◽  
Author(s):  
Zoran Markovic ◽  
Davor Perusko ◽  
Dragana Tosic ◽  
Nebojsa Romcevic ◽  
Miroslav Dramicanin ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrical Properties ◽  
Elevated Temperatures ◽  
Sodium Dodecyl ◽  
Copper Substrate ◽  
Carbon Matrix ◽  
Deposition Process ◽  
Single Wall Carbon Nanotubes ◽  
Single Wall Carbon ◽  
Deposited Films

Single wall carbon nanotubes (SWCNTs) represent an important group of nanomaterials with attractive electrical, chemical, and mechanical properties. In this work we have investigated the structural, optical and electrical properties of single wall carbon nanotube films deposited on copper substrate and then transferred to polymethyl methacrylate (PMMA). The properties of deposited films were varied by changing different parameters: substrate temperature, deposition time and electric field strength. Atomic force microscopy (AFM) has been used to study the deposition process of SWCNT films on copper substrate. AFM analysis has shown that sodium dodecyl sulfate (SDS) micellas were deposited on copper substrate before carbon nanotubes because of their higher mobility. Raman spectroscopy revealed that SWCNTs deposited at elevated temperatures are oxidized. FTIR results showed that COOH groups and Cu2O were generated during electrophoretic process. The SWCNT films were transferred to PMMA substrate and they achieved a sheet resistance of 360 ?/sq with 79% transparency at 550 nm wavelength and a strong adhesion to the substrate. The main reasons for higher values of sheet resistances of SWCNT thin films compared to those of other authors are oxidation of carbon nanotubes during electrophoresis and the presence of used surfactans in carbon matrix of deposited films.

Structures and electrical properties of barium strontium titanate thin films grown by multi-ion-beam reactive sputtering technique

1995 ◽  
Vol 10 (3) ◽  
pp. 708-726 ◽  
Author(s):  
C-J. Peng ◽  
S.B. Krupanidhi
Keyword(s):  
Dielectric Constant ◽  
Electrical Properties ◽  
Strontium Titanate ◽  
Electric Fields ◽  
Barium Strontium Titanate ◽  
Elevated Temperatures ◽  
Ion Beam ◽  
Type I ◽  
Type Ii ◽  
Barium Strontium

The structure and electrical properties of multi-ion beam reactive sputter (MIBERS) deposited barium strontium titanate (BST) films were characterized in terms of Ba/Sr ratio, substrate temperature, annealing temperature and time, film thickness, doping concentration, and secondary low-energy oxygen ion bombardment. Films deposited onto unheated substrates, followed by annealing at 700 °C showed lower dielectric constant (<200), compared to a dielectric constant of about 560 for those deposited at elevated temperatures, probably due to reduced voids. Two types of microstructures (type I and type II) were observed depending on the incipient phase of the as-grown films, which also led to two types of time domain dielectric response, Curie-von Schweidler and Debye type, respectively. The current-voltage (I-V) characteristics of type II films doped with high donor concentration showed a bulk space-charge-limited conduction (SCLC) with discrete shallow traps embedded in a trap-distributed background at high electric fields. The I-V characteristics of bombarded films deposited at higher substrate temperatures showed promising results of lower leakage currents and trap densities.

Differences in Electrical Properties of Portland Cement and Alkali-Activated Slag Mortars

2018 ◽  
Vol 276 ◽  
pp. 15-20 ◽  
Author(s):  
Pavel Rovnaník ◽  
Maria Míková ◽  
Ivo Kusák ◽  
Patrik Bayer
Keyword(s):  
Electrical Properties ◽  
Portland Cement ◽  
Building Materials ◽  
Elevated Temperatures ◽  
Sodium Ions ◽  
Alkali Activated Slag ◽  
Self Heating ◽  
Chemical Attack ◽  
Activated Slag ◽  
Alkali Activated

Alkali-activated slag is known as a building material for more than sixty years and is considered an alternative to Portland cement based binders. Compared to Portland cement it exhibits some superior properties such as higher resistance against chemical attack and exposure to elevated temperatures. Aluminosilicate binders are generally electrical insulators; however, electrical properties of building materials gain the importance in the new field of applications such as self-sensing or self-heating materials. This paper brings a comparison of the electrical properties, especially resistance and capacitance, between Portland cement and alkali-activated slag mortars. The measurements revealed that alkali-activated slag shows enhanced conducting properties due to the presence of mobile hydrated sodium ions and metallic iron microparticles.

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