DIELECTRIC PROPERTIES OF PLASMA POLYMERIZED N,N,3,5 TETRAMETHYLANILINE THIN FILMS

2011 ◽  
Vol 18 (01n02) ◽  
pp. 53-60 ◽  
Author(s):  
H. AKTHER ◽  
A. H. BHUIYAN
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Relaxation Times ◽  
Electrical Conductance ◽  
Low Frequency ◽  
Ring Structure ◽  
Frequency Region ◽  
Localized States ◽  
High Frequency Region ◽  
Capacitively Coupled

Plasma polymerized thin films of aluminium/thin film/aluminium configuration were deposited at room temperature by a parallel plate capacitively coupled glow discharge reactor using N,N,3,5 tetramethylaniline (TMA) as a precursor. The infrared spectroscopic analyses revealed that plasma polymerized TMA (PPTMA) films contained an aromatic ring structure with NC and CH side groups, presence of C = O was also evident. The differential thermal analysis and thermogravimetric analysis of PPTMA thin film was thermally stable up to about 505 K. The scanning electron microscopy of PPTMA thin film showed a smooth, flawless and pinhole free surface. The capacitance and ac electrical conductance of PPTMA thin films were measured as functions of frequency (100 < f < 105 Hz) and temperature (300 < T < 450 K). The electrical conductivity is more dependent on temperature in the low frequency region than that in the high frequency region. In PPTMA thin films the conduction may be dominated by hopping of carriers between the localized states at low temperatures and thermally excited at the high temperatures. The activation energies are estimated to be about 0.05 eV in the low temperature and 0.23 eV in the high temperature. Dielectric constant decreases with the increase of frequency and that decreases with the increase of temperature but dielectric loss increases with increasing frequency with a minimum in the low frequency region. The temperature-dependence of the Cole-Cole diagram shows the existence of distribution of dielectric relaxation times in the PPTMA thin films.

scholarly journals Frequency Dependent Electrical Properties of Ferroelectric Ba0.8Sr0.2TiO3 Thin Film

1970 ◽  
Vol 17 (2) ◽  
pp. 186-190 ◽  
Author(s):  
Ala’eddin A. SAIF ◽  
Zul Azhar ZAHID JAMAL ◽  
Zaliman SAULI ◽  
Prabakaran POOPALAN
Keyword(s):  
Thin Film ◽  
Dielectric Constant ◽  
High Frequency ◽  
Room Temperature ◽  
Electric Modulus ◽  
Low Frequency ◽  
Frequency Region ◽  
Electrical Parameters ◽  
High Frequency Region ◽  
Frequency Dependent

The frequency dependent electrical parameters, such as impedance, electric modulus, dielectric constant and AC conductivity for ferroelectric Ba0.8Sr0.2TiO3 thin film have been investigated within the range of 1 Hz and 106 Hz at room temperature. Z* plane shows two regions corresponding to the bulk mechanism and the distribution of the grain boundaries-electrodes process. M" versus frequency plot reveals a relaxation peak, which is not observed in the ε″ plot and it has been found that this peak is a non-Debye-type. The frequency dependent conductivity plot shows three regions of conduction processes, i. e., a low-frequency region due to DC conduction, a mid-frequency region due to translational hopping motions and a high-frequency region due to localized hopping and/or reorientational motion.http://dx.doi.org/10.5755/j01.ms.17.2.490

Anderson-Stuart Model to Analyze AC and DC Conductivity of Lithium Zinc-Silicate Glass / Glass-Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 919-924
Author(s):  
M.S. Jogad ◽  
V.K. Shrikhande ◽  
A.H. Dyama ◽  
L.A. Udachan ◽  
Govind P. Kothiyal
Keyword(s):  
High Frequency ◽  
Glass Ceramics ◽  
Low Frequency ◽  
Frequency Region ◽  
Dc Conductivity ◽  
Frequency Range ◽  
High Frequency Region ◽  
Dc Conductivities ◽  
Conductivity Variation ◽  
Different Temperatures

AC and DC conductivities have been measured by using the real (e¢) and imaginary (e¢¢) parts of the dielectric constant data of glass and glass-ceramics (GC) at different temperatures in the rage 297-642K and in the frequency range 100 Hz to 10 MHz. Using Anderson –Stuart model, we have calculated the activation energy, which is observed to be lower than that of the DC conductivity. The analysis for glass/glass-ceramics indicates that the conductivity variation with frequency exhibits an initial linear region followed by nonlinear region with a maximum in the high-frequency region. The observed frequency dependence of ionic conductivity has been analyzed within the extended Anderson–Stuart model considering both the electrostatic and elastic strain terms. In glass/glassceramic the calculations based on the Anderson-Stuart model agree with the experimental observations in the low frequency region but at higher frequencies there is departure from measured data.

Analysis of low frequency noise characteristics in p-type polycrystalline silicon thin film transistors

2017 ◽  
Vol 31 (19-21) ◽  
pp. 1740020
Author(s):  
Yuan Liu ◽  
Yun-Fei En ◽  
Wen-Xiao Fang
Keyword(s):  
Thin Film ◽  
Thin Film Transistors ◽  
Polycrystalline Silicon ◽  
Low Frequency ◽  
Gate Oxide ◽  
Localized States ◽  
Frequency Noise ◽  
Silicon Thin Film ◽  
Noise Characteristics ◽  
P Type

Low frequency noises in the p-type polycrystalline silicon thin film transistors are investigated. It shows a pure 1/f[Formula: see text] (with [Formula: see text] near one) noise behavior which can be explained by emission and trapping processes of carriers between trapping states. Subsequently, the gate voltage-dependent drain current noise power spectral densities closely follow the mobility fluctuation model, and the average Hooge’s parameter is then extracted. By considering traditional tunneling processes, the flat-band voltage spectral density is extracted and the concentration of traps in the grain boundary is calculated to be [Formula: see text]. By converting the frequency to tunneling depth of carriers in the gate oxide, the spatial distribution of gate oxide trapped charges are obtained. Finally, the distribution of localized states in the energy band is extracted. The experimental results show an exponential deep states and tail states distribution in the band gap while [Formula: see text] is about [Formula: see text], [Formula: see text] is [Formula: see text][Formula: see text]617 K, [Formula: see text] is [Formula: see text] and [Formula: see text] is [Formula: see text][Formula: see text]265 K.

scholarly journals Characterization of Nucleobases in Broadband Terahertz Spectra from 0.5 to 10 THz with the Air-Biased-Coherent-Detection Technique

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1148 ◽  
Author(s):  
Miao Yu ◽  
Shihan Yan ◽  
Yong-qiang Sun ◽  
Wang Sheng ◽  
Fu Tang ◽  
...  
Keyword(s):  
Low Frequency ◽  
Frequency Region ◽  
Coherent Detection ◽  
Detection Technique ◽  
Terahertz Time Domain Spectroscopy ◽  
High Frequency Region ◽  
Characteristic Absorption ◽  
Thz Range ◽  
Thz Absorption

Terahertz time-domain spectroscopy (THz-TDS) is an effective coherent detection technique for deeply understanding the structures and functions of biomolecules. However, generally not full information in the whole THz range can be obtained due to the limited detection bandwidth (usually less than 5 THz) of the traditional THz-TDS systems. In this paper, effective THz absorption spectra in 0.5–10 THz range of five typical nucleobases of DNA/RNA are characterized with a super broadband THz detection technique, called the air-biased- coherent-detection (THz-ABCD) technique. Few unexpected characteristic absorption peaks appeared in the low-frequency region and meanwhile a series of anticipated characteristic absorption peaks are found in the high-frequency region. The fingerprint spectra of these nucleobases are helpful for further analysis on the vibration and twisting behavior of hydrogen bonds, van der Waals and electrostatic forces etc. between and within DNA/RNA biomolecules.

SYNTHESIS, PIEZOELECTRIC, DIELECTRIC AND CONDUCTIVITY STUDIES ON Dy2O3 SUBSTITUTED (Bi0.94Na0.94)0.5Ba0.06TiO3 CERAMICS

2011 ◽  
Vol 01 (04) ◽  
pp. 455-464 ◽  
Author(s):  
K. SAMBASIVA RAO ◽  
HAILEEYESUS WORKINEH ◽  
A. SWATHI ◽  
B. S. KALYANI
Keyword(s):  
Low Frequency ◽  
Charge Carrier Concentration ◽  
Frequency Region ◽  
Relaxor Behavior ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
High Frequency Region ◽  
Pure Perovskite Structure ◽  
Universal Power Law ◽  
Diffraction Patterns

Polycrystalline ( Bi 0.94-x Dy x Na 0.94)0.5 Ba 0.06 TiO 3 ceramics (x = 0, 0.04, and 0.08, designated as BNBT6, BNBT6: 4Dy and BNBT6: 8Dy, respectively) were prepared by conventional high temperature sintering method. The X-ray diffraction patterns show pure perovskite structure with no secondary phases. Lattice parameters and unit cell volumes have decreased due to Dy2O3 substitution. SEM micrographs revealed denser samples (ρrel > 97%) with uniformly distributed grain sizes. The room temperature piezoelectric properties of Dy2O3 substituted sample at x = 0.04 were relatively higher: d33 = 147 pC/N, k p = 28% and Q m = 128. The samples exhibited infinitesimal change in thickness (≈ 15 nm) to an applied voltage of 100 V, which could be utilized in actuator applications. Relaxor behavior and broad dielectric maxima with diffuse phase transition were observed. The value of RT dielectric constant has increased while dielectric loss was decreased due to Dy2O3 substitution. Conductivity in the materials obeys Jonscher's universal power law. The conductivity in the low frequency region is associated with short range translational hopping while it is associated with the reorientational hopping in the high frequency region. The charge carrier concentration term remained constant over the entire temperature range of (30–500°C).

A Thin Cloud Removal Method for Optical Image Based on Improved Homomorphism Filtering

2014 ◽  
Vol 618 ◽  
pp. 519-522
Author(s):  
Guang Yu ◽  
Wen Bang Sun ◽  
Gang Liu ◽  
Mai Yu Zhou
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Frequency Component ◽  
Frequency Region ◽  
High Frequency Region ◽  
Filtering Method ◽  
Thin Cloud ◽  
Cloud Removal ◽  
Thin Cloud Removal ◽  
Image Definition

Optical remote image is affected by thin cloud inevitably, which debases image definition. Traditional homomorphism filtering frequently used in thin cloud removing has affect on the cloud in low frequency region, but is not effective for those in high frequency region. An improved homomorphism filtering method is proposed on the basis of statistical characters of image information. Instead of the filtering in frequency field, it isolates the low frequency component of the image representing cloud information with calculating neighborhood average in spatial field. Then, the filtered image is enhanced based on rough set. The experiment results show that the proposed method compared to traditional methods can obtain good results and performs faster.

Analysis of Sound Absorption Properties of Three-Leaf Microperforated Panel Absorbers without a Rigid Backing

2014 ◽  
Vol 937 ◽  
pp. 465-471
Author(s):  
Xiao Ling Gai ◽  
Xian Hui Li ◽  
Rui Wu ◽  
Bin Zhang ◽  
Jun Juan Zhao
Keyword(s):  
Sound Absorption ◽  
Low Frequency ◽  
Wide Frequency Range ◽  
Structure Design ◽  
Frequency Region ◽  
Theoretical Development ◽  
Frequency Range ◽  
Absorption Properties ◽  
High Frequency Region ◽  
Energy Dissipated

Microperforated panel (MPP) absorbers have been developed rapidly and used in many fields in recent years. First, based on the Maa’s theory, the theoretical development of MPP is reviewed in this paper. Furthermore, structure design and processing technology of MPP are introduced. Finally, the further development of MPP is discussed. Based on the MPP theory and electro-acoustical equivalent circuit principle, sound absorption properties of three-leaf microperforated panel (TMPP) absorbers without a rigid backing are studied to broaden the sound absorption bandwidth of MPP structure. Simulation results show that TMPP absorbers without a rigid backing have two resonance peaks and the energy dissipated coefficient remains constant in the low frequency range. The resonance frequency moves toward low frequency region with the increasing of the distance, thickness and pore diameter of MPP and moves toward high frequency region with the increasing of the perforation when other parameters keep invariant. The energy dissipated coefficient more than 0.5 over 8 octaves by choosing proper parameters. In conclusion, TMPP absorbers without a rigid backing have good sound absorption properties in a wide frequency range.

Modeling of Perforated Screens or Membrane Using Rigid Frame Porous Models Combined with Thin Membrane Resonance Sound Absorbing Theory

2013 ◽  
Vol 357-360 ◽  
pp. 1206-1211
Author(s):  
Xiao Ling Gai ◽  
Xian Hui Li ◽  
Bin Zhang ◽  
Peng Xie ◽  
Zhi Hui Ma
Keyword(s):  
High Frequency ◽  
Sound Absorption ◽  
Mass Density ◽  
Low Frequency ◽  
Frequency Region ◽  
Thin Membrane ◽  
High Frequency Region ◽  
Rigid Frame ◽  
Membrane Resonance

The sound absorption ability of screen or perforated membrane is studied based on rigid frame porous models combined with thin membrane resonance sound absorbing theory in this paper. Results show that the sound absorption of screen or perforated membrane is better considering the role of membrane than using the rigid frame porous models when the mass density of screen or perforated membrane is smaller. The rigid frame porous model is very accuracy to model the sound absorption ability of screen or perforated membrane when the mass density of membrane is greater. The parameter studies present that the sound absorption peaks move toward low frequency region with the increasing of the depth of air-back cavity, mass density and thickness of screens or perforated membrane and moves toward high frequency region with the increasing of the perforation and perforated radius of screens or perforated membrane when other parameters keep invariant.

Optical Study of PbTiO3 Thin Films Grown by Sol-Gel Technique

1994 ◽  
Vol 361 ◽  
Author(s):  
E. Ching-Prado ◽  
R.W. Tao ◽  
R.S. Katiyar ◽  
A.S. Bhalla
Keyword(s):  
Thin Films ◽  
Annealing Time ◽  
Sol Gel ◽  
Low Frequency ◽  
Frequency Region ◽  
Film Stress ◽  
Optical Study ◽  
High Background ◽  
Gel Technique ◽  
Homogeneous Film

ABSTRACTThin films of PbTiO3 were prepared by sol-gel method on platinum-coated-Si and Al2O3 and annealed at 600°C. The annealing time of the films, deposited on Si, were 6 and 12 hours, respectively. Micro-Raman spectra show high background in the low frequency region and the bands are broader with respect to the single crystal work, which indicates the polycrystalline nature of the samples. The film annealed for 12 hours showed more pronounced peaks in the spectra when compared to the film annealed for 6 hours. Micro-Raman measurements on different spots in the film indicate that the PT film on platinum-coated silicon substrate is highly inhomogeneous. In the case of PT/Al2O3 such studies show a homogeneous film. The frequencies of most of the modes are decreased, which is associated to grains under stress. The nature of the stress is discussed. Although film stress may not be homogeneous, a stress value around 1.2 GPa is estimated from Raman data. XRD and SEM techniques were used for structural characterization.

scholarly journals Image Fusion Algorithm at Pixel Level Based on Edge Detection

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Jiming Chen ◽  
Liping Chen ◽  
Mohammad Shabaz
Keyword(s):  
Edge Detection ◽  
Image Fusion ◽  
High Frequency ◽  
Low Frequency ◽  
Frequency Region ◽  
Experimental Comparison ◽  
Fusion Algorithm ◽  
High Frequency Region ◽  
Running Time ◽  
Low Efficiency

In the present scenario, image fusion is utilized at a large level for various applications. But, the techniques and algorithms are cumbersome and time-consuming. So, aiming at the problems of low efficiency, long running time, missing image detail information, and poor image fusion, the image fusion algorithm at pixel level based on edge detection is proposed. The improved ROEWA (Ratio of Exponentially Weighted Averages) operator is used to detect the edge of the image. The variable precision fitting algorithm and edge curvature change are used to extract the feature line of the image edge and edge angle point of the feature to improve the stability of image fusion. According to the information and characteristics of the high-frequency region and low-frequency region, different image fusion rules are set. To cope with the high-frequency area, the local energy weighted fusion approach based on edge information is utilized. The low-frequency region is processed by merging the region energy with the weighting factor, and the fusion results of the high findings demonstrate that the image fusion technique presented in this work increases the resolution by 1.23 and 1.01, respectively, when compared to the two standard approaches. When compared to the two standard approaches, the experimental results show that the proposed algorithm can effectively reduce the lack of image information. The sharpness and information entropy of the fused image are higher than the experimental comparison method, and the running time is shorter and has better robustness.

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