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The dielectric properties of synclinic (ferroelectric SmC*) and anticlinic (antiferroelectric SmCA*) smectic liquid crystals composed of molecules of one chiral version (S) are presented and compared with properties of racemic mixture (R, S), showing SmC and SmCA phases. The racemic mixture completely loses its ferroelectric and antiferroelectric properties. Surprisingly, only one dielectric mode observed in the antiferroelectric SmCA* phase disappeared in the dielectric response of the racemic SmCA phase. Additionally, we observed that in the SmC phase, seen in the racemic mixture, the weak dielectric mode (named the X mode) is detected, which seems to be the continuation of the PL mode existing in the racemic SmCA. Moreover, this mode in the racemic SmC has nothing to do with the Goldstone mode, typical for the SmC* phase. This paper describes in detail the real and imaginary parts of dielectric permittivity in smectic phases for the enantiomer and racemate with and without a DC field, compares the properties of the X and PL modes, and discusses the full scheme of dielectric modes in enantiomer and racemate. [ABSTRACT FROM AUTHOR]

The development of chemical sensor devices operating in non-contact mode is of primary interest due to the demand from various industries for a fast, simple and inexpensive determination of chemical composition in different media in a non-invasive way. One of the promising directions for the development of analytical devices with such characteristics is the use of high-frequency electrical signals. The paper discusses the evolution of high-frequency contactless conductometry method, likewise other methods and devices operating on similar physical principles (dielectric spectroscopy, microwave sensors, C4D detectors). [ABSTRACT FROM AUTHOR]

The macroscopic properties of polymer nanocomposites (PNC) rely largely on the interphase between the polymer chains and the filler particles. One significant difficulty to solve this issue is to quantitatively model the structure‐property correlations due to the interfacial region in these complex materials. While dielectric spectroscopy (DS) measurements are routinely used to characterize the effective permittivity of filled polymers, fitting standard effective medium models and mixing equations to these data remains notoriously difficult to interpret. This is due to the absence of explicit reference to internal length scales characterizing the interfaces in the PNC. As an illustrative example, a two‐level homogenization framework is proposed which enables the extraction of useful information on the impact of a thin interphase confined on a nanometer length scale based on broadband DS data. This model leads to new ways of tuning the interphase so as to optimize the material's response to electric field, a situation relevant for electromagnetic shielding. This approach provides guidance on how to observe directly and experimentally the actual properties of the interface between the phases (as opposed to model‐based inference). Aside from its secure physical foundation in the theory of effective medium, a significant advantage of this approach is that a genetic algorithm (GA) technique applied to this physics‐based model enables the uniqueness of the fit parameters to be considered, as the GA method is robust in terms of finding globally optimum solutions, therefore placing confidence in non‐universal values of the percolation exponents. Recent work in physics‐informed machine learning indicates that the effective dielectric properties of PNC with many degrees of freedom due to their complex morphology can be described by considering only a few degrees of freedom describing the interface features between the phases in these composites. [ABSTRACT FROM AUTHOR]

Interfacial characteristics of nanocomposites are critical limiting factors in the design of polymer nanocomposites. The nanocomposites have complex structures and play a pivotal role in controlling functional properties. Analysis of interfacial layers in polymer nanocomposites, existing between the polymer matrix and the nanoparticles plays a major role in determining their characteristics. High-frequency analysis of electrical conductivity and dielectric properties of carbon nanofillers which are embedded in an epoxy matrix were analysed using alternating current dielectric spectra. This article provides a correlation between the electrical transport properties and dielectric behaviour of epoxy carbon nanocomposites at different temperatures are investigated with variations in frequency. Electrical transport properties of nanocomposites are primarily dictated by electron tunnelling and matrix, nanofillers conductivity. Dielectric spectroscopy in the frequency range 10 Hz–8 MHz has been performed on epoxy nanocomposites with and without hybrid carbon nanofillers at one weight percentage (2:3 ratio). Dominant dielectric relaxation mode is observed in the base composite at a low-frequency region (≥10 Hz), whereas nanocomposite with hybrid carbon nanofillers is observed to induce two dielectric relaxations in the kHz region. Increase in non-monotonic variations in dielectric spectra makes the nanocomposite suitable for high temperature low sag conductor core, aerospace and cryogenic engineering applications. [ABSTRACT FROM AUTHOR]

This study is focused on investigating the role of bismuth oxide (Bi2O3) nanoparticles to improve structural, optical, electrical, and mechanical properties of low‐density polyethylene (LDPE). For this purpose, Bi2O3 nanoparticles were synthesized by using the solvothermal method and examined by transmission electron microscopes (TEM), x‐ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, and ultraviolet–visible (UV–Vis) light absorption methods. LDPE‐based nanocomposites were prepared by changing the nanoparticle additive ratio in the composite from 0% to 2% by weight. The composites were analyzed in the context of their FTIR spectra, atomic force microscope (AFM) images, UV–Vis light absorption spectra, stress–strain curves, and energy storage abilities. While the AFM findings indicate a smoother surface for the composites, the optical band gap analysis reveals a slightly decreased direct optical band gap energy. The analyses based on dielectric spectroscopy also highlight the LDPE/0.5% n‐Bi2O3 composite in terms of the best energy storage capability. Additionally, the highest Young's modulus, toughness, stress at break, and percentage of strain at break were also recorded for the LDPE/0.5% n‐Bi2O3 composite. In this context, the LDPE/0.5% n‐Bi2O3 composite with improved dielectric and mechanical properties can be suggested as a new promising LDPE‐based nanocomposite with better properties for industrial purposes. [ABSTRACT FROM AUTHOR]

The study investigated the effect of the molecular weight of three difunctional poly(propylene glycol) diacrylates on the temperature-dependent ionic conductivity of these monomers and their blends with an eutectic nematic liquid crystal mixture (E7). The results revealed two distinct regions. At low temperatures, ionic conduction can be described by the Vogel–Tamman–Fulcher (VTF) equation, while at high temperatures, the conductivity data follow the prediction of the Arrhenius model. The Arrhenius and VTF parameters and their corresponding activation energies were determined using the least squares method. In addition, a conductivity analysis based on an ionic hopping model is proposed. Estimates of ion concentrations and diffusion constants were calculated. It was found that both the ionic concentration and the diffusion constant decrease with the increase in the molecular weight of the monomers. The static dielectric permittivity decreases in the following order: TPGDA, PPGDA540, and PPGDA900. This can be explained by the higher dipole moment of TPGDA, which is caused by an enhanced volume density of carbonyl groups. [ABSTRACT FROM AUTHOR]

The results of dielectric relaxation spectroscopy of the chiral liquid crystal 4′-butyl-4-(2-methylbutoxy)azoxybenzene in the crystal phase are presented. The scaling procedure showed complex molecular dynamics and allows one to decompose the observed relaxation process into two closely located relaxation processes around the short molecular axis. Temperature dependences of relaxation times characterizing flip-flop motions (rotation around the short molecular axis) and rotation around the long molecular axis are of the Arrhenius type. [ABSTRACT FROM AUTHOR]

The problem of field induced phase transition into the ferroelectric phase in relaxor ceramics and in particular in PMN ceramics was studied for many years, but the results are still controversial. The temperature and field dependences of PMN polycrystalline ceramics dielectric spectra have been studied. The transitions from the glass-like into the ferroelectric phase were found both in field cooling and zero field heating after field cooling regimes under the fields above 3 kV/cm. Electric field scans near the diffuse maximum of the dielectric permittivity demonstrated the shift of the loss maximum to the high frequency at increasing of applied electric field. The experimentally observed frequency-dependent sign of the C–V effect (the decrease (negative effect) or the increase (positive effect) of dielectric permittivity at increasing field) is due to spectra hardening. In contrast to single crystal, where the application of the electric field higher than 1.6 kV/cm in <111> direction induces phase transition into ferroelectric state, in polycrystalline ceramics no clear evidence of the phase transition from the paraelectric into the ferroelectric state up to 6 kV/cm neither at 242 K nor at 246 K was found. This difference between the single crystal and polycrystalline ceramics can be explained by very strong dependence of the threshold field from the field orientation at this transition. The influence of external field on low frequency relaxation process parameters for PMN single crystal and ceramics is compared. [ABSTRACT FROM AUTHOR]

Objectives: Dielectric spectroscopy is commonly used for online monitoring of biomass growth. It is however not utilized for biomass concentration measurements due to poor correlation with Cell Dry Weight (CDW). A calibration methodology is developed that can directly measure viable biomass concentration in a commercial filamentous process using dielectric values, without recourse to independent and challenging viability determinations. Results: The methodology is applied to samples from the industrial scale fermentation of a filamentous fungus, Acremonium fusidioides. By mixing fresh and heat-killed samples, linear responses were verified and sample viability could be fitted with the dielectric Δ C values and total solids concentration. The study included a total of 26 samples across 21 different cultivations, with a legacy at-line viable cell analyzer requiring 2 ml samples, and a modern on-line probe operated at-line with 2 different sample presentation volumes, one compatible with the legacy analyzer, a larger sample volume of 100 ml being compatible with calibration for on-line operation. The linear model provided an R 2 value of 0.99 between Δ C and viable biomass across the sample set using either instrument. The difference in ∆C when analyzing 100 mL and 2 mL samples with an in-line probe can be adjusted by a scalar factor of 1.33 within the microbial system used in this study, preserving the linear relation with R 2 of 0.97. Conclusions: It is possible to directly estimate viable biomass concentrations utilizing dielectric spectroscopy without recourse to extensive and difficult to execute independent viability studies. The same method can be applied to calibrate different instruments to measure viable biomass concentration. Small sample volumes are appropriate as long as the sample volumes are kept consistent. [ABSTRACT FROM AUTHOR]

Viable cell concentration (VCC) is an essential parameter that is required to support the efficient cultivation of mammalian cells. Although commonly determined using at‐line or off‐line analytics, in‐line capacitance measurements represent a suitable alternative method for the determination of VCC. In addition, these latter efforts are complimentary with the Food and Drug Administration's initiative for process analytical technologies (PATs). However, current applications for online determination of the VCC often rely on single frequency measurements and corresponding linear regression models. It has been reported that this may be insufficient for application at all stages of a mammalian cell culture processes due to changes in multiple cell parameters over time. Alternatively, dielectric spectroscopy, measuring capacitance at multiple frequencies, in combination with multivariate mathematical models, has proven to be more robust. However, this has only been applied for retrospective data analysis. Here, we present the implementation of an O‐PLS model for the online processing of multifrequency capacitance signals and the on‐the‐fly integration of the models' VCC results into a supervisory control and data acquisition (SCADA) system commonly used for cultivation observation and control. This system was evaluated using a Chinese hamster ovary (CHO) cell perfusion process. [ABSTRACT FROM AUTHOR]

In spite of the significance from both scientific and technological viewpoints, systematical studies on the dielectric spectra of (K,Na)NbO 3 -based lead-free ceramics particularly in the poled state had been scarcely performed so far. In this study, the compositional series of (1- x)(K 0.48 Na 0.52)(Nb 0.96 Sb 0.04)O 3 − x (Bi 0.50 Na 0.50)ZrO 3 ceramics were chosen representatively to shed more light on the characters of dielectric properties. All the ceramics in the unpoled state show dielectric spectra of large dispersion with the relaxational characteristic frequency higher than the measured upper limit of 60 MHz at room temperature. Additional resonance peaks due to the electromechanical coupling of piezoelectric effect appear and are accompanied by a large step-like reduction of dielectric permittivity ε′ in the dielectric spectra after poling. An abnormal phenomenon that poling induces the increase of low-frequency ε′ occurs in those ceramics with x ≥ 0.04 at room temperature, and is confirmed to associate closely with the orthorhombic-tetragonal and rhombohedral-orthorhombic polymorphic phase transitions. Further study of domain structure indicates that the origin of this abnormal phenomenon should be ascribed to the enhancement of domain-wall mobility because of the large reduction of domain-wall density due to the poling. [ABSTRACT FROM AUTHOR]

Nematic–nematic transitions in a highly polar nematic compound are studied, in thick cells in which the molecules are aligned parallel to the substrates but perpendicular to the applied electric field, using dielectric spectroscopy in the frequency range 1 Hz to 10 MHz over a wide temperature range. The studied compound displays three nematic phases under cooling from the isotropic phase: ubiquitous nematic N; high polarizability NX; and ferroelectric nematic NF. Two collective processes were observed. The dielectric strength and relaxation frequency of one of the processes P2 showed a dependence on the thickness of the cell. The process P1 is the amplitude mode, while the process P2 is the phason mode. [ABSTRACT FROM AUTHOR]

One of the key points in the physics of the relaxors is their response to the applied DC field. Many studies of this topic were made, in particular on the influence of the field on the dielectric properties. However, practically, in all the cases, the measurements were performed at a fixed frequency and usually with the change in the temperature at the fixed field strength. In this paper, we report the evolution of the dielectric spectra at low frequencies (0.1 Hz < ω < 1 kHz) at fixed temperature 246 K on changing the DC electric field applied in (111) from 1 kV to 7 kV. Cole-Cole function was used to describe the spectra and the field dependences of the mean relaxation time τ , the oscillation strength Δ and the width parameter α were determined. The obtained τ (E) and Δ (E) provide evidence of the field-induced transition from the nonpolar glass-like phase to the nonpolar paraelectric phase at around 1.5 kV/cm. In the paraelectric phase, very fast hardening of the spectra was observed with τ changing from 10 s to about 10 − 4 s. The performed analysis demonstrated that the earlier reported positive C-V effect is completely determined by the spectra hardening, while Δ does not show any change in the glass-like phase and monotonously decreases with a field increase in the paraelectric state. For complete understanding of the microscopic origin of the observed phenomena, a detailed study on the short-and long-range structures at the same condition is necessary. [ABSTRACT FROM AUTHOR]

Dielectric spectroscopy (DS) is the primary technique to observe the dielectric properties of biomaterials. DS extracts complex permittivity spectra from measured frequency responses such as the scattering parameters or impedances of materials over the frequency band of interest. In this study, an open-ended coaxial probe and vector network analyzer were used to characterize the complex permittivity spectra of protein suspensions of human mesenchymal stem cells (hMSCs) and human osteogenic sarcoma (Saos-2) cells in distilled water at frequencies ranging from 10 MHz to 43.5 GHz. The complex permittivity spectra of the protein suspensions of hMSCs and Saos-2 cells revealed two major dielectric dispersions, β and γ , offering three distinctive features for detecting the differentiation of stem cells: the distinctive values in the real and imaginary parts of the complex permittivity spectra as well as the relaxation frequency in the β -dispersion. The protein suspensions were analyzed using a single-shell model, and a dielectrophoresis (DEP) study was performed to determine the relationship between DS and DEP. In immunohistochemistry, antigen–antibody reactions and staining are required to identify the cell type; in contrast, DS eliminates the use of biological processes, while also providing numerical values of the dielectric permittivity of the material-under-test to detect differences. This study suggests that the application of DS can be expanded to detect stem cell differentiation. [ABSTRACT FROM AUTHOR]

An explicit relation between half‐width at half‐maximum ΔT in a dissipation factor of dipolar molecular rotors in a solid phase and rotational barrier height Ub was derived within the Debye relaxation model. The formula for Ub is simply expressed as Ub≈1.317kT*2ΔT. Here, T* is the temperature at the peak position in the dissipation factor, and k is the Boltzmann constant. The formula is an alternative to the familiar Arrhenius equation, from which Ub has so far been estimated in various dielectric experiments. The distinction of the proposed formula is the determination of Ub from a single peak in a dissipation factor induced by an electric field, while the Arrhenius equation needs data for the magnitudes of the dissipation factor and temperatures at several peaks. By applying the proposed formula to dipole molecular rotors (ROT‐2F) in a single crystalline and polycrystalline, for which Ub values were reported (Horansky et al., Phys. Rev. B 74, 054306 [2006]), the calculated values of Ub were quantitatively reproduced. This indicates the validity of the proposed formula, and the formula is expected to be applied to the analysis of dielectric spectra of 2D dipolar molecular rotor systems. [ABSTRACT FROM AUTHOR]

We studied the dielectric properties of a polar nematic phase (NF) sandwiched between two gold or ITO electrodes, serving as a cell surface. In bulk, NF is expected to exhibit a Goldstone mode (phason), because polarisation can uniformly rotate with no energy cost. However, because the coupling between the direction of nematic director and polarisation is finite, and the confinement, even in the absence of the aligning surface layer, induces some energy cost for a reorientation of polarisation, the relaxation frequency of the phason mode is measured in a kHz regime. The phason mode is easily quenched by a bias electric field, which enables fluctuations in the magnitude of polarisation to be followed in both the ferroelectric and paraelectric nematic phases. This amplitude (soft) mode is also influenced by boundary conditions. A theory describing the phase and amplitude fluctuations in the NF phase shows that the free energy of the system and, consequently, the dielectric response are dominated by polarisation-related terms with the flexoelectricity being relevant only at a very weak surface anchoring. Contributions due to the nematic elastic terms are always negligible. The model relates the observed low-frequency mode to the director fluctuations weakly coupled to polarisation fluctuations. [ABSTRACT FROM AUTHOR]

BACKGROUND: The rapid and accurate identification of colostrum, a strong non‐homogeneous food, remains a challenge. In the present study, the dielectric spectra including the dielectric constant (ε′) and loss factor (ε″) of 154 colostrum samples adulterated with 0–50% mature milk were measured from 20 to 4500 MHz. RESULTS: The results showed that the noise‐reducing spectral preprocessing, including Savitzky–Golay (S‐G), second derivative (SD), and S‐G + SD, was significantly better than scattering‐eliminating, including standard normal variate (SNV), multiplicative scatter correction (MSC), and SNV + MSC. The combination of S‐G and SD was the best. Principal component analysis results demonstrated that dielectric spectroscopy is less susceptible to the inhomogeneity of colostrum and can be used to identify doped colostrum. The identification performance of linear models was better than that of non‐linear models. The established linear discriminant analysis model based on full spectra had the best accuracy rates of 99.14% and 97.37% in the calibration and validation sets, respectively. Confirmatory tests on samples from different sources confirmed the satisfactory robustness of the proposed model. CONCLUSION: We found that the main unfavorable effect on the identification based on dielectric spectroscopy was noise interference, rather than scattering effect caused by inhomogeneity of colostrum. The satisfactory results undoubtedly cast light on rapid detection of strongly non‐homogeneous foods based on dielectric spectroscopy. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Dielectric spectroscopy in the sub-THz regime is a promising candidate for microfluidic-based analysis of biological cells and bio-molecules, since multiple vibrational and rotational transition energy levels exist in this frequency range (P. Siegel, "Terahertz technology in biology and medicine," IEEE Trans. Microw. Theor. Tech., vol. 52, pp. 2438–2447, 2004). This article presents our recent efforts in the implementation of microfluidic channel networks with silicon-based technologies to unleash the potential of an integrated sub-THz microfluidic sensor platform. Various aspects of dielectric sensors, readout systems, flowmeter design as well as implemention- and technology-related questions are addressed. Three dielectric sensor systems are presented operating at 240 GHz realizing transmission-based, reflection-based and full two-port architectures. Furthermore different silicon based microchannel integration techniques are discussed as well as a novel copper pillar-based PCB microchannel method is proposed and successfully demonstrated. [ABSTRACT FROM AUTHOR]

The nonhomogeneity of bovine colostrum leads to strong scattering effects for electromagnetic waves, which affects the application of electromagnetic spectroscopy in detecting colostrum. This work aimed to compare the performance of near-infrared spectroscopy (NIRS) and dielectric spectroscopy (DS) in quantitatively predicting the content of mature milk as an adulterant in colostrum. The near-infrared spectra in the range of 833 to 2,500 nm and the dielectric spectra in the range of 20 to 4,500 MHz of 150 adulterated colostrum samples containing 0 to 50% mature milk were analyzed. The different proportions of mature milk in colostrum significantly changed near-infrared and dielectric spectra. The principal component analysis score plot showed that both NIRS and DS could identify the proportion of mature milk in colostrum, but the 2 methods had different characteristics. Linear partial least squares regression and nonlinear least squares support vector machine (LSSVM) models based on near-infrared and dielectric spectra were established to identify doping proportions. The results showed that DS had better identification performance with a root-mean-square error of prediction of 4.9% and a residual prediction deviation of 3.441 by successive projection algorithm LSSVM, whereas NIRS was relatively weak with a root-mean-square error of prediction of 7.3% and a residual prediction deviation of 2.301 by full-spectra LSSVM. This work provides important insights for the quantitative prediction of nonhomogeneous liquid food by DS. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, new results on the degradation of losartan potassium (LP, (1)), in the absence and presence of excipients, which was induced by UV light, the acid character of phosphate buffer solution (PBS) and alkaline medium, respectively, are reported through correlated studies of FTIR spectroscopy, photoluminescence and dielectric spectroscopy. The photoluminescence (PL) spectra of LP and the drug marked under the name Lorista (LO) are characterized by intense emission bands, peaking at 378 nm and 380 nm, respectively, accompanied by low intensity bands with a maximum at ~450–460 nm. Photodegradation of LO in a solid state is evidenced by a decrease in the intensity of the PL band at 380 nm, a variation that originates both in the adsorption of water vapors from the air and in the interaction of LP with excipients such as cornstarch, silicon dioxide and cellulose. The LP-water interaction is described, taking into account the main electrical parameters, i.e., complex dielectric permittivity and electrical conductivity. Photodegradation of LP and LO also induces an increase in the intensity of the emission band, at ~450–460 nm. The influence of acid and alkaline medium on the LO degradation is analyzed using phosphate buffer (PBS) and NaOH solutions, respectively. In both cases, a decrease in the intensity of the PL band, at 380 nm, is reported. The intensity diminution of the PL spectra of NaOH-reacted LP and LO is the result of the formation of the photodegradation product N-methanolamide-{[2′-(1H-tetrazol-5-yl)(1,1′-biphenyl)-4-yl]methyl} (2). This compound was proven by the studies of FTIR spectroscopy achieved on LP and NaOH-reacted LP. The appearance of the IR band at 1740 cm−1 and the increase in the absorbance in the IR band at 1423 cm−1 indicate that the photodegradation product (2) contains the C=O and C-OH functional groups. [ABSTRACT FROM AUTHOR]

Hydrogen-bonded liquid crystals (HBLC) formed by mixing 4-alcyloxy-2-fluorobenzoic acid (nOBAF) and the 4-pentyl-4-biphenylcarbonitrile (5CB) at (1:1), (1:3) and (3:1) (mol/mol) ratios have been investigated. Four HBLC series are prepared by changing the carbon chain length from 7 to 10 designated 5CB/nOBAF. The fluorobenzoic acids (nOBAF) are the proton donors while the pyridine unit (5CB) is the proton acceptors. Thermal behaviour and phase diagrams of the individual series have been established using differential scanning Calorimetry (DSC) and polarising optical microscopy (POM). It was found that all complexes exhibit nematic (N) and smectic G (SmG) phases. For the nematic phase, the dielectric anisotropy was increased while the thresholds voltage was decreased. This can be explained by the strong longitudinal dipole moment of the nematic phase compared to the nOBAF compounds. Furthermore, as the alkoxy chain length increases, the birefringence, response time, rotational viscosity, and splay elastic constant all decrease by the way of the reduction of the order parameter for the longer chains. In addition, hydrogen-bonded proton transfer between cyano and carboxylic acid groups have been explored by Fourier transform infrared spectroscopy (FTIR) for the first time. [ABSTRACT FROM AUTHOR]

This article provides an overview of frequency domain dielectric spectroscopy measurements and the techniques for data analysis. Examples are used to illustrate key points in formulating the experiments and analyzing the data. [ABSTRACT FROM AUTHOR]

This paper studies the dielectric spectra of solid solutions (SS) of the system (1 − x − y)NaNbO3– x KNbO3 – y CdNb2O6 y = 0.075, x = 0.05 ÷ 0.30 in the temperature range (10 ÷ 900) K. The formation of a local maximum was established in the interval (260 ÷ 300) K at small x  values, which, as KNbO3 increases, is gradually blurred and becomes an inflection point. Detected in SS with x = 0.05 ÷ 0.10, the shift of the maxima of dependences ′/ 0(T) and ′′/ 0 (T), depending on the frequency of the electric field at the temperature ranges (300 ÷ 304) K and (258 ÷ 271) K, is not related to relaxation. This anomaly may indicate a crystallographic disorder to A and B positions. The conclusion is made about the expediency of using the obtained results for the development of functional ferroactive materials. [ABSTRACT FROM AUTHOR]

Rapeseed is one of the most important sources of vegetable oil worldwide. Knowledge of the dielectric properties of rapeseed may be beneficial for moisture content determination and the optimization of microwave treatment processes. The aim of this research was to examine the complex dielectric permittivity spectra of rapeseed of moisture content from 8.3% to 16.1%. The measurements were performed in the 20 MHz–3 GHz frequency range with the use of a vector network analyzer and a coaxial transmission-line cell. The real part of dielectric permittivity significantly depended on the water content of the seeds. The obtained spectra were modeled with the use of a three-pole Debye model with bulk electrical conductivity. Because the highest-frequency pole was found near the high-frequency measurement band limit, the spectra were additionally modeled with the use of an approximate ABC model with two in-band Debye poles. The determined model parameters were found to be highly dependent on the water content of the seeds. The relations between these parameters and water content were analyzed. [ABSTRACT FROM AUTHOR]

The molecular dynamics of two addition type polynorbornenes, exo‐PNBSi and PTCNSi1, bearing microporosity has been investigated by broadband dielectric spectroscopy, fast scanning calorimetry, and neutron scattering. Both polymers have the same side groups but different backbones. Due to their favorable transport properties, these polymers have potential applications in separation membranes for gases. It is established in literature that molecular fluctuations are important for the diffusion of small molecules through polymers. For exo‐PNBSi, two dielectric processes are observed, which are assigned to Maxwell/Wagner/Sillars (MWS) process due to blocking of charge carriers at internal voids or pore walls. For PTCNSi1, one MWS‐polarization process is found. This points to a bimodal pore‐size distribution for exo‐PNBSi. A glass transition for exo‐PNBSi and for PTCNSi1 could be evidenced for the first time using fast scanning calorimetry. For Tg and the corresponding apparent activation energy, higher values were found for PTCNSi1 compared to exo‐PNBSi. For both polymers, the neutron scattering data reveal one relaxation process. This process is mainly assigned to methyl group rotation probably overlayed by carbon–carbon torsional fluctuations. [ABSTRACT FROM AUTHOR]

This paper describes a novel dielectric spectroscopic technique to investigate the milk freshness and adulterated agents using a customized, open-ended, coaxial probe. An inversely proportional relationship was found between temperature and shelf-life and the real part of the complex permittivity (e') of the samples at 0.1-3GHz. At 2GHz, a linear relationship was found in e' and e", storage time, and water content. In addition, total of five adulterants' agents were investigated and a linear relationship was found between both e' and e" parts, and their concentrations (R² > 0.99). This approach could be the potential basis of rapid online milk quality monitoring in milk production facilities. [ABSTRACT FROM AUTHOR]

The influence of various types of nanoparticle fillers with the same diameter of 20 nm were separately incorporated into a single component impregnating resin based on a polyesterimide (PEI) matrix and its subsequent changes in complex relative permittivity were studied. In this paper, nanoparticles of Al 2 O 3 and ZnO were dispersed into PEI (with 0.5 and 1 wt.%) to prepare nanocomposite polymer. Dielectric frequency spectroscopy was used to measure the dependence of the real and imaginary parts of complex relative permittivity within the frequency range of 1 mHz to 1 MHz at a temperature range from +20 °C to +120 °C. The presence of weight concentration of nanoparticles in the PEI resin has an impact on the segmental dynamics of the polymer chain and changed the charge distribution in the given system. The changes detected in the 1 H NMR spectra confirm that dispersed nanoparticles in PEI lead to the formation of loose structures, which results in higher polymer chain mobility. A shift of the local relaxation peaks, corresponding to the α -relaxation process, and higher mobility of the polymer chains in the spectra of imaginary permittivity of the investigated nanocomposites was observed. [ABSTRACT FROM AUTHOR]

Detection of bioparticles is of great importance in electrophoresis, identification of biomass sources, food and water safety, and other areas. It requires a proper model to describe bioparticles' electromagnetic characteristics. A numerical study of Escherichia coli bacteria during their functional activity was carried out by using two different geometrical models for the cells that considered the bacteria as layered ellipsoids and layered spheres. It was concluded that during cell duplication, the change in the dielectric permittivity of the cell is high enough to be measured at radio frequencies of the order of 50 kHz. An experimental setup based on the capacitive Wheatstone bridge was designed to measure relative changes in permittivity during cell division. In this way, the theoretical model was validated by measuring the dielectric permittivity changes in a cell culture of Escherichia coli ATTC 8739 from WDCM 00012 Vitroids. The spheroidal model was confirmed to be more accurate. [ABSTRACT FROM AUTHOR]

In this work, a magnetodielectric coupling observed in barium titanate–cobalt ferrite composites synthesized using high-energy ball milling assisted via a thermal treatment is discussed. Vibrating sample magnetometry and dielectric spectroscopy showed that multiferroic composites possess both ferromagnetic and dielectric behaviors inherited from the parent ferromagnetic cobalt ferrite and ferroelectric barium titanate phases. The magnetocapacitance (up to 35%) recorded for x = 0.3, (1-x)BaTiO 3 –xCoFe 2 O 4 , can be attributed to the spin-dependent filtering mechanism. The composite with the aforementioned composition exhibited a homogeneous matrix–particle composite microstructure, which was achieved via high-energy ball milling during the mixing stage. [ABSTRACT FROM AUTHOR]

This article deals with the topical problem of estimating water content in water–oil mixtures within porous media they saturate, according to low-field NMR relaxometry and dielectric spectroscopy. The aim of the research is experimental validation of the capability of complex data interpretation to acquire information on the filtration-volumetric properties of drill cuttings, relaxation characteristics of oil-containing fluids, the water/oil ratio in water–oil mixtures, and their saturation of drill cuttings to control the composition of liquids produced from boreholes. The studies are carried out on samples of cuttings and oils taken from fields in the Northern regions of the West Siberian oil-and-gas province, where NMR studies have not been performed before. Based on the experimental data obtained, the possibility of water content assessment in water-in-oil mixtures and porous media they saturate were proved through NMR relaxometry. With the use of the proposed methodology, the amount of water in oil–water mixtures was established, and their main NMR characteristics were determined. The relative error in evaluating the proportion of water in mixtures based on high-viscosity oils is less than 10%, and about 20% for those based on light oils. When determining the oil–water ratio in the pore space of the drill cuttings, the error is about 15%. It was proven that joint use of these two techniques makes it possible to increase the reliability of the oil–water ratio assessment of all the samples studied. Furthermore, it was revealed that the NMR spectrum shifts to the right, and the spectrum of the complex permittivity shifts downwards during the transition from high-viscosity oils to light ones. [ABSTRACT FROM AUTHOR]

[Display omitted] • Binary mixtures of bent-core liquid crystals show columnar and smectic phases with good miscibility. • All mixtures show mesomorphic behaviour, with reductions in their clearing points and liquid crystalline ranges. • The mixtures show strong dielectric response mainly promoted by the presence of ester groups in the bent-core molecules. • Reversible trans -to- cis photoisomerization of azobenzenes is applied to tune the molecular dipole moment, assessed by DFT. • Irradiation increases the conductivity of the equimolar mixture by two orders of magnitude. We report the mesomorphic behaviour, dielectric and ferroelectric properties, and computational modelling of binary mixtures containing two bent-core liquid crystals: the so-called NG75-COO (3,4́- Bis[4-(4-n-tetradecyloxybenzoyloxy)benzoyloxy]biphenyl), which forms smectic phases, and IP31- AzB (3,4′ - Bis[4-(4-n-tetradecyloxyphenylazo)benzoyloxy]biphenyl), which forms columnar phases. The phase diagram, assessed by polarised optical microscopy, shows that the binary mixtures retain the mesophase behaviour of the major component, whilst the equimolar mixture displays smectic-type phases. Dielectric and ferroelectric analyses were carried out on samples containing 10%, 50%, and 90% of IP31-AzB (molar %), and we also investigated structure–property correlations by differential functional theory. The NG75-COO/IP31-AzB mixtures undergo strong dielectric and ferroelectric response due to the presence of highly polarisable groups in the bent-core components, particularly at the ester groups. All the mixtures under study exhibit light-responsiveness induced by reversible E -to- Z photoisomerization (trans -to- cis) of the azobenzene group in IP31-AzB, together with an increase in the molecular dipole moment. The potential to tune the phase behaviour of the mixtures, as well as their dielectric and ferroelectric responses, are investigated by light irradiation under different conditions of intensity and temperature. [ABSTRACT FROM AUTHOR]

• The compatibility between the matrix and nanofiller improves with the adding of fluorine. • Both dopants have enhanced the thermal stability of nanocomposites; fluorine protects the polymer from thermal decomposition. • Both fluorine and nitrogen enhance the dielectric constant; nitrogen suppresses the dielectric loss at high temperature. Polyvinylidene fluoride (PVDF) based polymer nanocomposites with ceramics as nanofiller have been investigated as a solution for energy storage devices due to their unique and attractive combination of processability and electrical properties. This work assesses two dopants (fluorine and nitrogen) for zinc oxide (ZnO) nanoparticles PVDF matrix composites as a means of improving dielectric properties targeting capacitive storage. Fluorine doping achieves improved performance compared to pure ZnO nanocomposites increasing the decomposition temperature by 15 °C to 463 °C with 15 wt% F-doped ZnO and reducing the weight loss by 4.2 %. The highest dielectric constant that can be achieved with the addition of fluorine is about 70 at room temperature, which is more than 3 times greater than that of pure ZnO nanocomposite. Nitrogen doping also enhances the permittivity of the nanocomposites at ambient temperature but limit enhancement at high temperature due to the lower activation energy. [ABSTRACT FROM AUTHOR]

The dielectric characteristics of kaolinite masses at 200 – 3500 kHz were investigated. The effect of the humidification of a mass on the values of the real and imaginary components of the permittivity is considered. The samples were obtained from the clay of Orenburg Oblast, mixed with distilled water containing > 70% (by weight) kaolinite with particle sizes represented by three modal maxima, μm: 0.14 ± 0.05, 1.13 ± 0.40, and 23.4 ± 2.70. It was determined that the dielectric constant of humid (26.5%) samples is equal to twice that of dry samples (7.8%) and triple that of fired samples (≈ 0%). It is shown that the dielectric constant is a quadratic function of the humidification. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study of the dielectric response in single crystals of barium strontium niobate doped with thulium of various concentrations. It is shown that the dielectric permittivity increases with increasing concentration of thulium. For as-grown samples the dispersion of the permittivity is observed in the frequency region of 106 Hz. The dependence is not observed for the samples polarized under DC field. For all the samples studied, the switched polarization increases and the coercive field decreases under action of an AC field. [ABSTRACT FROM AUTHOR]

This paper reports the design, simulation and experimental validation of an accurate liquid sensing technique in the nano-liter range. It is suitable for the detection and quantification of very small contents of liquid samples containing biological cells. The biosensor is based on an open-ended interdigitated capacitor (IDC) within a microfluidic channel. The microwave structure including the IDC is patterned in coplanar waveguide technology. The microfluidic channel is $100 \mu \text{m}$ thick and the IDC covers an area of $150 \mu \text{m}$ width and $90 \mu \text{m}$ length. This leads to a volume under analysis much lower than a nano-liter which allows the noninvasive and contactless microwave investigation of biological cells in their culture medium. This micro-device is used to extract the complex permittivity of liquid media from the measured scattering parameters within the frequency band ranging from 0.2 to 25 GHz. For ease of use, a SMA-connectorized version of the device with spring contacts probes to the biosensor is also proposed. Results concerning microparticle detection within the media are also presented, extending the use of the sensors to cellular environments. [ABSTRACT FROM AUTHOR]

The paper presents some general patterns of the temperature behavior of thermodepolarization currents, dielectric permittivity and conductivity of dielectric materials containing water molecules or hydrogen bonds – crystallohydrates, polyelectrolytes, and biopolymers. The results indicate that the anomalies of these properties are observed at 4, 20, 35, 46, 65–76°С, which are "threshold points" of water, when its structure changes abruptly. The observed anomalies are probably due to a change in the proton energy at a transition to an excited level in the double-well potential at heating, while the equilibrium of the system is achieved by slow stepwise heating. [ABSTRACT FROM AUTHOR]

Sn2P2(SexS1-x)6 (x = 0.1, 0.2 and 0.3) crystals were grown by the vapor transport technique and their dielectric, pyroelectric and ferroelectric properties in the vicinity of phase transition were evaluated. The dielectric properties of the investigated crystals show clear anomalies associated with the ferroelectric-paraelectric phase transitions in all the compositions. The spontaneous polarization behavior of Sn2P2(SexS1-x)6 crystals in the vicinity of the ferroelectric-paraelectric phase transition is discussed. The knowledge about the ferroelectric responses of Sn2P2(SexS1-x)6 crystals in a broad temperature range is essential for applications in the energy storage technology. The aim of this work was to investigate the dielectric, pyroelectric and ferroelectric properties of Sn2P2(SexS1-x)6 with different selenium content and compare to the parent compounds Sn2P2S6 and Sn2P2Se6. [ABSTRACT FROM AUTHOR]

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 ( C P – G) 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/ = (T – T 0) / C. The real ( Z ′) and imaginary ( Z ′ ′ ) parts of the electrical modulus were calculated from the various values of ′ and ′ ′ . It is shown that AC conductivity satisfies the relation σ (ω) ∞ ω n , where the power exponent n depends on temperature and frequency. From Arrhenius equation, the activation energies E σ and E h are also calculated which describes the complete conduction mechanism of dipaCl. [ABSTRACT FROM AUTHOR]

In this work, we propose a current-mode dielectric spectroscopy integrated circuit (IC) for the detection of liquids permittivity at microwave frequency range. The current-mode sensing scheme presents wideband operation with enhanced dynamic range compared to conventional voltage-mode sensing approach. A low intermediate frequency (IF) receiver architecture further provides better performances in flicker noise, dc offset, and harmonic mixing that degrade a sensor accuracy in zero-IF receiver architecture. Measured maximum conversion gain is 31.4 dB at 0.4 GHz RF frequency, while the 1dB-compression point ($P_{\text{1}dB}$) is measured to be -8 dBm at 1 GHz RF frequency. The operation frequency of the proposed spectroscopy IC is from 50 MHz to 4 GHz according to 3 dB bandwidth. The permittivity measurements for propanol across the frequency range of 0.03-10 GHz are performed with root mean square (rms) permittivity error of 0.49. The dielectric spectroscopy IC is fabricated in 28-nm CMOS technology with active area of 0.5 mm × 0.2 mm only, while consuming 13 mW from a 1.2 V supply. [ABSTRACT FROM AUTHOR]

The gas chromatography-mass spectrometry and dielectric spectroscopy techniques are used to characterize the thermodynamic properties of the essential oils extracted from two main Mediterranean wildland fuels, namely eucalyptus leaves and Pinus halepensis needles. These oils are assumed to be representative of the fuels organic volatile components that exhibit different fire behaviors. The relaxation frequencies determined from the peak of the imaginary permittivity spectra using the Havriliak–Negami empirical law revealed the Arrhenius dependence on temperature. Two activation energies are obtained: the first is around 4.13 kJ/mol for both species, and the second activation energy is around 1.27 kJ/mol for the Pinus halepensis essential oil and around 2.15 kJ/mol for the eucalyptus essential oil. Qualitative and quantitative composition differences are observed with GC–MS measurements for eucalyptus leaves and Pinus halepensis needles essential oils. [ABSTRACT FROM AUTHOR]

Using an open-ended coaxial probe and a vector network analyzer (VNA) is a conventional technique for the noninvasive and broadband measurement of dielectric permittivity. The method is widely applied to characterize bulk material and liquids and has recently been extended to thin sheet material samples. However, it is commonly believed that the method is not suitable in the high-frequency regime as perfect contact between the probe and the sample is required. Furthermore, the method is limited with respect to the characterization of thin sheet samples made of low-loss materials. In this article, we analyzed the main causes of these limitations, namely, low sensitivity, probe resonances, and the occurrence of air gaps between probe and samples. We also discuss and demonstrate solutions to overcome some of these limitations and improve the accuracy by introducing a lossy platform and an effective air-gap calibration algorithm. These improvements lead to a reliable and robust framework to characterize thin and flat dielectric samples, even at high frequencies and in high-permittivity regimes. [ABSTRACT FROM AUTHOR]

The so-called Fröhlich entropy is the entropy variation of a material under the application of an electric field. This quantity can be calculated, under suitable hypotheses, from the measured real part of the static dielectric function, when the imaginary part is negligible. Although Fröhlich entropy is defined for a biased sample, a straightforward physical interpretation correlates it to the state-of-order of the considered physical system in absence of field. When Fröhlich entropy is calculated from experimental results, its trend is able to give several information about the evolution in temperature of the explored compound, especially of its phase transition features. We here provide a comprehensive review of the physical systems (dipolar liquids and nematicons, organic molecular crystals, metallic nanoparticles, inorganic disordered ferroelectrics, etc.) where this approach has been exploited with the aim of evaluating their state of order and its temperature evolution. The variety of compounds where this method has been applied demonstrates that the estimation of the Fröhlich entropy can be considered a trustworthy tool for carrying out study on the state-of-order of different classes of materials. Indeed Fröhlich entropy evaluation can be considered a fruitful and reliable investigation technique which can be exploited alongside more usual experimental approaches.

Recently, wideband dielectric spectroscopy (WBDS) has been applied for material characterization. Milk spectroscopy is usually done with high-cost contact-based methods using a vector network analyzer (VNA). Non-contact WBDS of milk is a novel and convenient technique, which can be utilized for milk qualification. In this paper, an ultra-wideband time domain dielectric spectroscopy system for milk characterization is presented. The proposed setup is a quasi-monostatic free space dielectric spectroscopy in which all measurements are done with Xethru X4 sensor. Material under test is located in the far-field of Xethru sensor. The Fast Fourier Transform (FFT) of received time domain signals is computed and the permittivity of low-fat pasteurized cow milk and mixture of untreated raw cow milk and water have been estimated by mapping phase and amplitude differences of calibration materials. Mean squared error (MSE) of permittivity for low-fat milk and milk with different water content are 0.29% and below 0.056%, respectively. [ABSTRACT FROM AUTHOR]

• Polymeric optical adhesive NOA65 functionalized by additive ionic liquid (IL). • The refractive index and transmission of doped NOA65 uninfluenced by IL addition. • Dielectric characteristics in relation to IL doping concentration and temperature. • Activation energy of DC electrical conductivity reduced by doping IL into NOA65. • (Pseudo-)dielectric heating behaviors caused by (pseudo-)dielectric relaxation. Conductive polymers that exhibit exceptional electrical conductivity have garnered significant interests in recent decades, disclosing remarkable potentials across a broad range of industries. In this study we investigated a series of Norland UV-curable optical adhesive (NOA65) doped with ionic liquid (1-hexyl-3-methylimidazolium bis(trifluormethylsulfonyl)imide) at various concentrations from 0 wt% to 2.0 wt%. The refractive indices of the doped prepolymers and photopolymerized NOA65 were examined by Abbe refractometry with four wavelength filters at distinct temperatures. Moreover, the transmission spectra, frequency-dependent complex dielectric and conductivity properties of the composites were explored in comparison with their pristine precursor and photopolymer. Interestingly, by applying an alternating electric field within a specific frequency range, we found that these samples can undergo unique dielectric relaxation, and thus give rise to the observed heating effect. Our preliminary results demonstrate that the conductivity of the proposed polymer composites is significantly higher than that of the undoped counterpart, whereas the refractive index, dispersion, and transmission remain virtually unchanged, revealing great promise for real applications in optoelectronic technology. [ABSTRACT FROM AUTHOR]

Dielectric spectroscopy is employed to study the relaxation phenomena in natural polyhydroxyalkanoates (PHAs) upon temperature and frequency variations. Effects of PHAs molecular structure on the relaxation, arising from the differences in monomeric composition, are investigated under identical conditions in a frequency range of 10−2–106 Hz, and at different temperatures. All PHA samples showed different dielectric response at different temperature. Primary α -relaxation signals are observed at temperature corresponding to the glass transition temperature. On the other hand, secondary β - and γ -relaxations are detected at low temperatures, and attributed to local motions of polar groups and small segments of the polymer chain. The dielectric properties of representative PHA samples are compared and discussed. [ABSTRACT FROM AUTHOR]

We investigated the impact of two types of nanoparticles, magnetic (γFe2O3) and nonmagnetic one (CeO2) dispersed in nematic 5CB matrix. Dielectric spectroscopy was used to investigate the dielectric behavior of the nematic 5CB doped by both kinds of nanoparticles. By fitting a suitable equivalent electric circuit model to the experimental data we show the change of electro–physical parameters of the nematic in the bulk and at the nematic–electrode interface. It is found that the impedance modulus decreases with increasing the concentration of nanoparticles. This increase is attributed to an increase of the conductivity, which is related to the mobile charge carriers accumulating near the electrodes. For nonmagnetic nanoparticles, both the diffusion constant D and the mobility μ were increased with increasing concentration. Surprisingly, for magnetic nanoparticles, the increase of D and μ is followed by a considerable decrease at concentration higher than 3%. [ABSTRACT FROM AUTHOR]

Dielectric spectroscopic measurements of five homologous series of orthoconic antiferroelectric liquid crystalline (OAFLC) esters (S)-MHPOBC ((S)-4-(1-methylheptyloxy) carbonyl phenyl 4'-octyloxy-4-biphenylcarboxylate) has been investigated. The investigated compound contains SmC*, SmCA* and SmA phase with SmCA* phase at a broad temperature range. Parameters such as absorption curve, dispersion curve, Cole-Cole plot, relaxation frequency, relaxation time, dielectric strength and electrical conductivity has been discussed. The structure property correlations of these compounds are also highlighted in the light of the dielectric measurements. Compound S1.6 (FF) and S2.6 (FH) has dielectric strength of around 250 in the SmC* phase due to the presence of Goldstone mode. [ABSTRACT FROM AUTHOR]

The effective clinical management of cancer is entirely dependent on the detection at a suitable early time as well as on the proper diagnosis. The main aim of this review is to survey the applications of dielectric spectroscopy in the clinical cancer diagnosis and distinguishing between normal and tumor tissues. This review focuses on the recognition of the biophysical properties of normal and malignant tissues and also of biophysical changes elicited by cancers comprising (breast, liver, thyroid gland, lung, skin, bladder, uterine and ovarian, lung, and prostate) tumors. These biophysical changes are often produced because of the difference in tissue composition, blood flow, and architecture between normal and malignant cells. From the literature, it has been observed that dielectric spectroscopy method can be applied before, during or after tumor surgery; and most of the results are confirmed by conventional analysis such as histopathology. Moreover, by dielectric spectroscopy technique, dielectric parameters, especially conductivity, and permittivity were suggested to be biomarkers for the densification of cancerous patients of the previously mentioned cancer types. It could be concluded that dielectric spectroscopy rapidly provides the biophysical status of normal tissues and cancerous ones and thus can be applied effectively for the early diagnosis and detection of cancers. It could be a promising diagnostic tool in the future. [ABSTRACT FROM AUTHOR]

In the present study, dielectric spectroscopy was used to assess the influence of ELF (1-200 Hz) electromagnetic fields over protein relaxation from activated sludge (approx. 99% water content), sampled from the biological tank of a domestic wastewater treatment plant. Dielectric loss (tgδ) was determined for both activated sludge samples and autoclaved samples. Experimental data analysis shows that biological samples (activated sludge) have different dielectric behavior than the sterile samples (sterilized sludge). Unlike sterile samples in which the function tgδ vs. frequency is continuous, in the activated sludge samples, this function presents two discontinuities specific to electrical resonances around the frequencies of 26.5 Hz and 50.1 Hz. This behavior indicates that under the influence of the measuring signal of 26.5 Hz and 50.1 Hz, biochemical processes are stimulated in activated sludge. Also, the significant changes in the number of charge carriers suggest that, at these frequencies, changes occur in the mechanism and kinetics of biochemical processes. [ABSTRACT FROM AUTHOR]

In this work we present the results of study of the influence of Eu doping on temperature behavior of the dielectric response and conductivity in the frequency range of 10 Hz–1 MHz and the temperature range of 300–750 K, and low temperature (5–400 K) specific heat of the Na1/2Bi1/2TiO3 (NBT) single crystals. It is shown that volume conductivity of NBT is thermally activated with activation energies Ea = 75 meV at T < 320 K and Ea = 700–900 meV at T > 620 K. Eu doping of NBT modifies the behavior of the conductivity with the activation energy being the same at T < 320 K and the deviation of the dependency from Arrhenius law for T > 320 K. Although the comparison of the results of dielectric response experiments for NBT and NBT:Eu3+ reveals significant changes of lattice dynamics induced by Eu doping at T > 320 K, the behavior of the low temperature specific heat remains almost the same. [ABSTRACT FROM AUTHOR]