scholarly journals Impedance Spectroscopy, Electrical Relaxation and Ac Conductivity Studies of an Organic-Inorganic Hybrid Compound: C12H14N2CuCl4

2009 ◽  
Vol 5 (3) ◽  
pp. 741-752 ◽  
Author(s):  
W. Wamani ◽  
R. Elwej ◽  
T. Mhiri ◽  
Mohamed Belhouchet
Keyword(s):  
Ac Conductivity ◽  
Arrhenius Equation ◽  
Constant Phase Element ◽  
Equivalent Circuit Model ◽  
Relaxation Model ◽  
Frequency Range ◽  
Scanning Calorimetry ◽  
Bulk Resistance ◽  
Hybrid Compound ◽  
Translation Motion

The AC conductivity of the compound, C12H14N2CuCl4, in the temperature and frequency range from 373 to 423 K and 209 Hz – 5 MHz, respectively, is reported. The differential scanning calorimetry and thermogravimetric analysis indicate the presence of a phase transition at 400 K. The Z’ and Z’’ vs. frequency plots are found to be well fit by using the equivalent circuit model. The circuits consist of a parallel combination of bulk resistance Rp and constant phase element. Besides, the analysis of the experimental data based on the jump relaxation model shows that the translation motion of the charge carrier and reorientation hopping between the equivalent sites of the metal chloride anion and the cation groups are responsible for the observed AC conductivity in the temperature regions I (373–400 K) and II (400–423 K). The frequency dependence of the conductivity which follows the Arrhenius equation is interpreted in terms of Jonscher's law: σ (ω) = σdc +A ω S. 

scholarly journals Impedance spectroscopy, electrical relaxation and Ac conductivity studies of organic-inorganic hybrid compound: NH3(C6H4)2NH3HgCl4

2011 ◽  
Vol 7 (2) ◽  
pp. 1348-1358 ◽  
Author(s):  
W. Wamani ◽  
N. Hannachi ◽  
T. Mhiri ◽  
M. Belhouchet
Keyword(s):  
Phase Transition ◽  
Impedance Spectroscopy ◽  
Equivalent Circuit ◽  
Ac Conductivity ◽  
Equivalent Circuit Model ◽  
Electrical Impedance Spectroscopy ◽  
Electrical Measurements ◽  
Scanning Calorimetry ◽  
Hybrid Compound ◽  
Inorganic Hybrid

Organic–inorganic hybrid sample NH3(C6H4)2NH3HgCl4 was characterized by differential scanning calorimetry (DSC), TGA analysis and electrical impedance spectroscopy. DSC studies indicated the presence of a one-phase transition at 391 K. As for the ac conductivity of the compound NH3(C6H4)2NH3HgCl4, it has been measured in the temperature range of 358 - 413K and the frequency range of 209 Hz–5 MHz. Concerning the Z’ and Z’’ versus frequency plots, they were well-fitted to an equivalent circuit model. The equivalent circuit is composed of a series of combination of two parallel (R//CPE) circuits. Besides, the frequency dependence of the conductivity was interpreted in terms of Jonscher's law σ(ω) = σdc +A ωn.  As regards the conductivity, it follows the Arrhenius relation. The variation of the value of the conductivity with temperatures confirmed the availability of the phase transition at 391K detected by DSC and electrical measurements.

scholarly journals Characterization and Electrical Properties of [C6H9N2]2CuCl4 Compound

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
M. Hamdi ◽  
A. Oueslati ◽  
I. Chaabane ◽  
F. Hlel
Keyword(s):  
Small Polaron ◽  
Equivalent Circuit Model ◽  
Scanning Calorimetry ◽  
Bulk Resistance ◽  
X Ray ◽  
Compound C ◽  
Vibrational Study ◽  
Primary Mechanism ◽  
Constant Phase Elements ◽  
Alternative Current

We report measurements of X-ray powder diffraction, vibrational study, the differential scanning calorimetry (DSC), and the electric properties of a made-up [C6H9N2]2CuCl4 sample. The alternative current (ac) conductivity of the compound [C6H9N2]2CuCl4 has been measured in the temperature range 356–398 K and the frequency range 209 Hz–5 MHz. The Cole-Cole (the imaginer part (Z′′) versus real part (Z′) of impedance complex) plots are well fitted to an equivalent circuit model which consists of a parallel combination of a bulk resistance (R) and constant phase elements (CPE). The single semicircle indicates only one primary mechanism for the electrical conduction within [C6H9N2]2CuCl4. The variation of the value of these elements with temperatures confirmed the result detected by DSC and dielectric measurements. Thus the conduction in the material is probably due to a hopping or a small polaron tunneling process.

scholarly journals Design and Analysis of Super Wideband Antenna for Microwave Applications

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 477
Author(s):  
Warsha Balani ◽  
Mrinal Sarvagya ◽  
Ajit Samasgikar ◽  
Tanweer Ali ◽  
Pradeep Kumar
Keyword(s):  
Communication Systems ◽  
Equivalent Circuit Model ◽  
Wireless Communication Systems ◽  
Impedance Bandwidth ◽  
Frequency Range ◽  
Fractional Bandwidth ◽  
Wide Bandwidth ◽  
Wireless Applications ◽  
Frequency Constraint ◽  
Time Domain Characterization

In this article, a compact concentric structured monopole patch antenna for super wideband (SWB) application is proposed and investigated. The essential characteristics of the designed antenna are: (i) to attain super-wide bandwidth characteristics, the proposed antenna is emerged from a traditional circular monopole antenna and has obtained an impedance bandwidth of 38.9:1 (ii) another important characteristic of the presented antenna is its larger bandwidth dimension ratio (BDR) value of 6596 that is accomplished by augmenting the electrical length of the patch. The electrical dimension of the proposed antenna is 0.18λ×0.16λ (λ corresponds to the lower end operating frequency). The designed antenna achieves a frequency range from 1.22 to 47.5 GHz with a fractional bandwidth of 190% and exhibiting S11 < −10 dB in simulation. For validating the simulated outcomes, the antenna model is fabricated and measured. Good conformity is established between measured and simulated results. Measured frequency ranges from 1.25 to 40 GHz with a fractional bandwidth of 188%, BDR of 6523 and S11 < −10 dB. Even though the presented antenna operates properly over the frequency range from 1.22 to 47.5 GHz, the results of the experiment are measured till 40 GHz because of the high-frequency constraint of the existing Vector Network Analyzer (VNA). The designed SWB antenna has the benefit of good gain, concise dimension, and wide bandwidth above the formerly reported antenna structures. Simulated gain varies from 0.5 to 10.3 dBi and measured gain varies from 0.2 to 9.7 dBi. Frequency domain, as well as time-domain characterization, has been realized to guide the relevance of the proposed antenna in SWB wireless applications. Furthermore, an equivalent circuit model of the proposed antenna is developed, and the response of the circuit is obtained. The presented antenna can be employed in L, S, C, X, Ka, K, Ku, and Q band wireless communication systems.

INFLUENCE OF La2O3 ADDITIONS ON CHEMICAL DURABILITY AND DIELECTRIC PROPERTIES OF BOROALUMINOSILICATE GLASSES

2012 ◽  
Vol 19 (06) ◽  
pp. 1250062 ◽  
Author(s):  
X. H. ZHANG ◽  
Y. L. YUE ◽  
H. T. WU
Keyword(s):  
Dielectric Properties ◽  
Chemical Durability ◽  
Tangent Loss ◽  
Frequency Range ◽  
Scanning Calorimetry ◽  
Glass Transition Temperatures ◽  
Weight Losses ◽  
Quenching Method ◽  
Scanning Electron

Boroaluminosilicate glasses containing La2O3 were prepared by the normal quenching method. The glass transition temperatures (Tg) were measured by differential scanning calorimetry (DSC). The structural role of RO was investigated by nuclear magnetic resonance (NMR). Chemical durability was evaluated by weight losses of glass samples after immersion in HC1 solution. High resolution scanning electron microscopy (HR-SEM) was used to examine the surface micrographs of corroded glass samples. The dielectric constant and tangent loss were measured in the frequency range 10–106 Hz. The results revealed that chemical durability and dielectric properties increased with increasing La2O3 content.

The structures and phase transitions in 4-aminopyridinium tetraaquabis(sulfato)iron(III), (C5H7N2)[FeIII(H2O)4(SO4)2]

2019 ◽  
Vol 75 (6) ◽  
pp. 1144-1151
Author(s):  
Tamara J. Bednarchuk ◽  
Wolfgang Hornfeck ◽  
Vasyl Kinzhybalo ◽  
Zhengyang Zhou ◽  
Michal Dušek ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Single Crystal ◽  
Room Temperature ◽  
Variable Temperature ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Hybrid Compound ◽  
Space Group ◽  
X Ray

The organic–inorganic hybrid compound 4-aminopyridinium tetraaquabis(sulfato)iron(III), (C5H7N2)[FeIII(H2O)4(SO4)2] (4apFeS), was obtained by slow evaporation of the solvent at room temperature and characterized by single-crystal X-ray diffraction in the temperature range from 290 to 80 K. Differential scanning calorimetry revealed that the title compound undergoes a sequence of three reversible phase transitions, which has been verified by variable-temperature X-ray diffraction analysis during cooling–heating cycles over the temperature ranges 290–100–290 K. In the room-temperature phase (I), space group C2/c, oxygen atoms from the closest Fe-atom environment (octahedral) were disordered over two equivalent positions around a twofold axis. Two intermediate phases (II), (III) were solved and refined as incommensurately modulated structures, employing the superspace formalism applied to single-crystal X-ray diffraction data. Both structures can be described in the (3+1)-dimensional monoclinic X2/c(α,0,γ)0s superspace group (where X is ½, ½, 0, ½) with modulation wavevectors q = (0.2943, 0, 0.5640) and q = (0.3366, 0, 0.5544) for phases (II) and (III), respectively. The completely ordered low-temperature phase (IV) was refined with the twinning model in the triclinic P{\overline 1} space group, revealing the existence of two domains. The dynamics of the disordered anionic substructure in the 4apFeS crystal seems to play an essential role in the phase transition mechanisms. The discrete organic moieties were found to be fully ordered even at room temperature.

scholarly journals Sugar Concentration Measurement System Using Radiofrequency Sensor

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2354
Author(s):  
Gerardo Aguila Rodriguez ◽  
Nayda Patricia Arias Duque ◽  
Blanca Estela Gonzalez Sanchez ◽  
Oscar Osvaldo Sandoval Gonzalez ◽  
Oscar Hernan Giraldo Osorio ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Measurement System ◽  
Ac Conductivity ◽  
Experimental Error ◽  
Sucrose Solution ◽  
Measuring System ◽  
Sugar Solution ◽  
Frequency Range ◽  
Tan Δ ◽  
Radiofrequency Sensor

A sugar solution measurement system was developed based on the dielectric properties of the sucrose molecule. An ac conductivity and tan δ study as a function of the frequency was performed to find the suitable frequency range for the measuring system. The results indicate that it is possible to obtain a better response of the sensor using the frequencies as the maxima peak in tan δ appears. Developed setup for sucrose solution was appropriate to measure in a 0.15 to 1 g/mL range with an experimental error of about 3%. The proposed system improves the measurement time over some other methods.

Dielectric Analysis Of Semi-Crystalline Poly(Ethylene Terephthalate)

1994 ◽  
Vol 347 ◽  
Author(s):  
Jianghua Wei ◽  
Richard Delgado ◽  
Martin C. Hawley ◽  
Mark T.Demeuse
Keyword(s):  
Dielectric Properties ◽  
Ethylene Terephthalate ◽  
Dielectric Analysis ◽  
Frequency Range ◽  
Fixed Frequency ◽  
Scanning Calorimetry ◽  
Fixed Temperature ◽  
Temperature Range ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene

ABSTRACTDielectric properties of poly(ethylene terephthalate) (PET) were measured over a frequency range of 10 KHz to 2.45 GHz and a temperature range of 20 to 110°C. Relaxation peaks were identified at 1) fixed frequency with variable temperatures, and 2) fixed temperature with variable frequencies. The crystallinity of poly (ethylene terephthalate) was measured using differential scanning calorimetry (DSC). Relationships between crystallinity, dielectric properties, and location of the dielectric relaxation peak on the frequency and temperature scales were studied for poly(ethylene terephthalate). Also, the dielectric loss factor decreases with increased crystallinity at 2.45 GHz and 4 GHz within the temperature range studied.

IN SITU SYNTHESIS, CHARACTERIZATION AND FREQUENCY DEPENDENT AC CONDUCTIVITY OF POLYANILINE/CoFe2O4 NANOCOMPOSITES

2011 ◽  
Vol 01 (03) ◽  
pp. 357-362 ◽  
Author(s):  
G. D. PRASANNA ◽  
H. S. JAYANNA
Keyword(s):  
Ac Conductivity ◽  
Room Temperature ◽  
In Situ Polymerization ◽  
In Situ Synthesis ◽  
Electron Micrograph ◽  
Frequency Range ◽  
X Ray Diffraction ◽  
Scanning Electron Micrograph ◽  
X Ray

The polyaniline (PANI)/ CoFe2O4 nanocomposites were prepared by an In Situ polymerization of aniline in an aqueous solution. The composites were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectrum,thermogravimetric analysis (TGA) and scanning electron micrograph (SEM). The AC conductivity and dielectric properties of these composites were investigated in the frequency range 1 kHz–10 MHz at room temperature. The AC conductivity was found to be constant up to 1 MHz and thereafter it increases steeply and it was observed maximum for the PANI with 60 wt% of CoFe2O4 nanocomposite. At lower frequencies the values of dielectric constant is maximum for pure CoFe2O4 nanoparticles.

A Modeling Method of Wideband Devices Based on Modified Nodal Analysis

2012 ◽  
Vol 182-183 ◽  
pp. 1323-1327
Author(s):  
Feng Lu ◽  
Jia Lu
Keyword(s):  
Equivalent Circuit Model ◽  
Measured Data ◽  
Model Fit ◽  
Maximum Relative Error ◽  
Frequency Range ◽  
Circuit Partitioning ◽  
Nodal Analysis ◽  
Modified Nodal Analysis ◽  
Simulation Results ◽  
Verification Process

According to the simplified circuit partitioning principle, this paper improves the Modified Nodal Analysis(MNA) of wideband Equivalent Circuit Model(ECM). The form of upconversion impedance is transformed from series into parallel. The results show that in the parallel form, the verification process of impedance type has been eliminated and it will not introduce new nodes. At the same time, the amount of computation has been reduced. The maximum relative error of measured data with this model fit is less than 0.693%. The simulation results and ECM test data are consistent with better at 0 to 8GHz frequency range.

scholarly journals Dielectric, impedance, modulus spectroscopy and AC conductivity studies on novel organic ferroelectric diisopropylammonium chloride (dipaCl)

2021 ◽  
pp. 2150015
Author(s):  
Mamataj Khatun ◽  
Ekramul Kabir
Keyword(s):  
Dielectric Property ◽  
Hydrochloric Acid ◽  
Dielectric Permittivity ◽  
Ac Conductivity ◽  
Conduction Mechanism ◽  
Arrhenius Equation ◽  
Methanol Solution ◽  
Power Exponent ◽  
Electrical Modulus ◽  
Modulus Spectroscopy

Organic molecular ferroelectric diisopropylammonium chloride (dipaCl) was successfully synthesized using diisopropylamine, hydrochloric acid (57%) and methanol solution. Dielectric permittivity, impedance, modulus spectroscopy and conductivity were systematically studied by Capacitance–Conductance ([Formula: see text] – [Formula: see text] measurements in the temperature range of 373–445 K. Dielectric property tests clearly show that the organic molecular ferroelectric dipaCl obeys Curies–Weiss law 1/[Formula: see text] = ([Formula: see text]–[Formula: see text]/[Formula: see text]. The real (Z′) and imaginary (Z′′) parts of the electrical modulus were calculated from the various values of 𝜀′ and 𝜀′′. It is shown that AC conductivity satisfies the relation [Formula: see text], where the power exponent [Formula: see text] depends on temperature and frequency. From Arrhenius equation, the activation energies [Formula: see text]and [Formula: see text] are also calculated which describes the complete conduction mechanism of dipaCl.

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