Dielectric study on dynamics of water in polymer matrix using a frequency range 106–1010 Hz

1990 ◽  
Vol 93 (1) ◽  
pp. 760-764 ◽  
Author(s):  
Naoki Shinyashiki ◽  
Nobuyuki Asaka ◽  
Satoru Mashimo ◽  
Shin Yagihara
Keyword(s):  
Polymer Matrix ◽  
Dielectric Study ◽  
Frequency Range

scholarly journals Terahertz Time-Domain Spectroscopy of Graphene Nanoflakes Embedded in Polymer Matrix

2019 ◽  
Vol 9 (3) ◽  
pp. 391 ◽  
Author(s):  
Anton Koroliov ◽  
Genyu Chen ◽  
Kenneth M. Goodfellow ◽  
A. Nick Vamivakas ◽  
Zygmunt Staniszewski ◽  
...  
Keyword(s):  
Polymer Matrix ◽  
Time Domain ◽  
Thz Radiation ◽  
Complex Conductivity ◽  
Frequency Range ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
Graphene Nanocomposites ◽  
Graphene Nanoflakes ◽  
Exfoliated Graphene

The terahertz time-domain spectroscopy (THz-TDS) technique has been used to obtain transmission THz-radiation spectra of polymer nanocomposites containing a controlled amount of exfoliated graphene. Graphene nanocomposites (1 wt%) that were used in this work were based on poly(ethylene terephthalate-ethylene dilinoleate) (PET-DLA) matrix and were prepared via a kilo-scale (suitable for research and development, and prototyping) in-situ polymerization. This was followed by compression molding into 0.3-mm-thick and 0.9-mm-thick foils. Transmission electron microscopy (TEM) and Raman studies were used to confirm that the graphene nanoflakes dispersed in a polymer matrix consisted of a few-layer graphene. The THz-radiation transients were generated and detected using a low-temperature–grown GaAs photoconductive emitter and detector, both excited by 100-fs-wide, 800-nm-wavelength optical pulses, generated at a 76-MHz repetition rate by a Ti:Sapphire laser. Time-domain signals transmitted through the nitrogen, neat polymer reference, and 1-wt% graphene-polymer nanocomposite samples were recorded and subsequently converted into the spectral domain by means of a fast Fourier transformation. The spectral range of our spectrometer was up to 4 THz, and measurements were taken at room temperature in a dry nitrogen environment. We collected a family of spectra and, based on Fresnel equations, performed a numerical analysis, that allowed us to extract the THz-frequency-range refractive index and absorption coefficient and their dependences on the sample composition and graphene content. Using the Clausius-Mossotti relation, we also managed to estimate the graphene effective dielectric constant to be equal to ~7 ± 2. Finally, we extracted from our experimental data complex conductivity spectra of graphene nanocomposites and successfully fitted them to the Drude-Smith model, demonstrating that our graphene nanoflakes were isolated in their polymer matrix and exhibited highly localized electron backscattering with a femtosecond relaxation time. Our results shed new light on how the incorporation of exfoliated graphene nanoflakes modifies polymer electrical properties in the THz-frequency range. Importantly, they demonstrate that the complex conductivity analysis is a very efficient, macroscopic and non-destructive (contrary to TEM) tool for the characterization of the dispersion of a graphene nanofiller within a copolyester matrix.

Dielectric Properties of Pure and Strontium Doped Nano-Hydroxyapatite

2013 ◽  
Vol 209 ◽  
pp. 151-155 ◽  
Author(s):  
Kashmira P. Tank ◽  
Bhoomika V. Jogiya ◽  
Dinesh K. Kanchan ◽  
Mihir J. Joshi
Keyword(s):  
Dielectric Constant ◽  
Applied Field ◽  
Room Temperature ◽  
Dental Enamel ◽  
Dielectric Study ◽  
Frequency Range ◽  
Xrd Study ◽  
Nano Crystalline ◽  
Crystalline Nature ◽  
Inorganic Matrix

Hydroxyapatite (Ca10(PO4)6(OH)2-HAp), is an excellent inorganic biomaterial and finds various applications. As it is similar to inorganic matrix of human bone and dental enamel, pure and doped HAps are widely studied. In the present study, pure nano-HAp and Strontium doped nano-HAp (Sr-HAp) with different concentrations were synthesized by surfactant mediated approach. The doping of strontium was confirmed by EDAX. The powder XRD study was carried out and it suggested nano-crystalline nature of the sample and the extra peaks observed other than HAp were due to the presence of brushite phase for higher concentration of Sr. TEM study revealed the needle type morphology for all the samples with size ranging from 23 nm to 78 nm. The dielectric study was carried out at room temperature within the frequency range from 102 Hz to 107 Hz and the variations of dielectric constant with frequency of applied field as well as with the concentration of strontium were studied. The results are discussed.

Dielectric study on dynamics and structure of water bound to DNA using a frequency range 107-1010 Hz

1989 ◽  
Vol 93 (12) ◽  
pp. 4963-4967 ◽  
Author(s):  
Satoru Mashimo ◽  
Toshihiro Umehara ◽  
Shinichi Kuwabara ◽  
Shin Yagihara
Keyword(s):  
Dielectric Study ◽  
Frequency Range ◽  
Structure Of Water

Dielectric study on chain dynamics of poly(glutamic acid) in aqueous solution using the frequency range 107-1010 Hz

1989 ◽  
Vol 22 (3) ◽  
pp. 1285-1288 ◽  
Author(s):  
Satoru Mashimo ◽  
Tsuneo Ota ◽  
Naoki Shinyashiki ◽  
Shinichi Tanaka ◽  
Shin Yagihara
Keyword(s):  
Aqueous Solution ◽  
Glutamic Acid ◽  
Dielectric Study ◽  
Frequency Range ◽  
Chain Dynamics

Dielectric study of allyl chloride with 2-butanol in microwave frequency range

2013 ◽  
Author(s):  
A. P. Maharolkar ◽  
Y. S. Sudake ◽  
S. P. Kamble ◽  
A. G. Murugkar ◽  
S. S. Patil ◽  
...  
Keyword(s):  
Allyl Chloride ◽  
Microwave Frequency ◽  
Dielectric Study ◽  
Frequency Range

scholarly journals Structural, Dielectric and Electrical Properties of Zirconium Doped Barium Titanate Perovskite

1970 ◽  
Vol 32 (2) ◽  
Author(s):  
Shamima Choudhury ◽  
Shurayya Akter ◽  
MJ Rahman ◽  
AH Bhuiyan ◽  
SN Rahman ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Barium Titanate ◽  
Loss Factor ◽  
Room Temperature ◽  
Sintering Temperature ◽  
Small Addition ◽  
Dielectric Study ◽  
Frequency Range ◽  
Doped Barium Titanate ◽  
Academy Of Sciences

The microstructural and electrical properties of pure and Zirconium (Zr) doped Barium titanate (BT) samples with general formula Ba(Ti1-xZrx)O3 (where x=0.0, 0.1, 0.2 and 0.3), prepared by high temperature solid state reaction at a sintering temperature of 1250° C, were investigated. Dielectric and structural properties of BT ceramics is influenced significantly by small addition of ZrO2. Scanning Electron Microscope (SEM) observations revealed enhanced microstructural uniformity and retarded grain growth with increasing Zr content. The dielectric study with frequency at room temperature in the frequency range 75 kHz to 30 MHz shows that dielectric constant decreases with increasing frequency. The resistivity of the samples shows asymptotic behavior with the variation of frequency and was found to be of the order of ~103 Ω-m. Loss factor of the grown materials decreased with increasing frequency but it became independent at higher frequency range. doi: 10.3329/jbas.v32i2.2434 Journal of Bangladesh Academy of Sciences Vol.32(2) 2008 151-159

scholarly journals Dielectric Study of Allyl Chloride with 2-Pentanone and 2-Hexanone in Microwave Frequency Range

2012 ◽  
Vol 33 (10) ◽  
pp. 3423-3426 ◽  
Author(s):  
Yuvraj Sudake ◽  
Siddharth Kamble ◽  
Aruna Maharolkar ◽  
Sunil Patil ◽  
Prakash Khirade ◽  
...  
Keyword(s):  
Allyl Chloride ◽  
Microwave Frequency ◽  
Dielectric Study ◽  
Frequency Range
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