Diffraction Peak Intensity Research Articles

Enhancing Resistant Starch Content of High Amylose Rice Starch through Heat-Moisture Treatment for Industrial Application.

The objective of the present study is to enhance the resistant starch (RS) content of high amylose rice starch with heat–moisture treatment (HMT) for industrial application. The optimized HMT condition for achieving the highest RS content established using response surface methodology (RSM) was a temperature of 100 °C, moisture content of 24.2%, and a time of 11.5 h. Upon HMT, the RS content increased from 32.1% for native starch to 46.4% in HMT starch with optimized condition. HMT of the starches reduced the solubility and swelling power. The surface of HMT starch granules was more irregular than native starch. The X-ray diffraction (XRD) peak intensity at 2θ = 5° was greatly reduced by HMT, and the peaks at 22.7° and 24.2° were merged. HMT increased the gelatinization temperature and reduced the gelatinization enthalpy. HMT provides a method for the production of high-yield RS2 with high amylose rice starch in industrial application.

Tuning Structural and Optical Properties of WO3 NPs Thin Films by the Fluency of Laser Pulses

In this paper, tungsten oxide thin films were successfully synthesized by the laser pulse deposition (PLD) method using a pulsed laser (ND-YAG) and wavelength (1064 nm) on a glass substrate at different laser fluencies. The effect of increasing laser fluency, on the optical and structural properties of WO3 nanoparticle thin films, was investigated by UV-Visible spectrophotometer, X-Ray diffraction (XRD), atomic force microscope (AFM) and Scanning Electron Microscope (SEM). X-Ray measurements for all samples of WO3 NPs thin films have shown that by increasing the laser fluencies from 5.175 to 6.369 J/cm2, the intensity of the (2 01) diffraction peak increases due to the film continuing to grow with increased crystallization.

Phase Transition between Crystalline Variants of Ordinary Ice.

Water is one of the most abundant molecules on Earth. However, this common and "simple" material has more than 18 different phases, which poses a great challenge to theoretically study the nature of water and ice. We designed two reaction coordinates that can distinguish between water and various ice states and used them to efficiently sample all possible states of the system in all-atom molecular dynamics simulation at ambient temperature and pressure. Various structural and thermodynamics properties, including the water-ice phase diagrams, can thus be calculated. We also present a simple model that successfully explains the thermodynamic stability of different ice states. Our work provides effective methods and data for theoretical studies of different phases of water and ice.

Optimization of Operating Parameters for Coal Low-Temperature Ashing: A Suitable and Efficient Treatment Method for Mineral Analysis in Coal

Low-temperature oxygen-plasma ashing plus X-ray diffraction analysis is one of the effective techniques to identify minerals in coal. However, previous publications have not provided any details of the exact low-temperature degrees and corresponding working conditions of ashers, and this could lead to two adverse effects without proper operating guidance: (1) a relatively high temperature (e.g., >150 °C) may cause alteration of minerals (particularly clay minerals), and (2) a relatively low temperature (e.g., <80 °C) may cause a long ashing time and incomplete ashing of organic matter. In this study, the authors introduced the most frequently used low-temperature plasma ashers (PVA TePla IoN 40 made in America and Quorum K1050X made in Britain) to reveal optional operating parameters for low-temperature ashing. The ashing effects were analyzed from the aspects of ash mass, X-ray diffraction patterns, and the qualitative and quantitative analysis of minerals. Considering all the factors above, it is concluded that the ashing is the best when the running power is 200 W for the IoN 40, at which the diffraction peaks of chlorite d(004) and kaolinite d(002) can be clearly distinguished by LTAs-XRD analysis. In addition, different low temperatures have certain influence on the crystal structure of minerals. When the power rises to above 300 W (about 150 °C), the crystal structure of minerals undergoes changes. The symmetry and integrity of the mineral peaks became worse, and destructive interference occurred between the spacing of reflection planes, resulting in significant decrease in diffraction peak intensity; thus, some trace minerals were unable to be identified. The study on the working parameters of the instrument would be helpful to ash coals more effectively and make qualitative and quantitative analysis of minerals more accurate.

Effects of Potassium Loading over Iron–Silica Interaction, Phase Evolution and Catalytic Behavior of Precipitated Iron-Based Catalysts for Fischer-Tropsch Synthesis

Potassium (K) promoter and its loading contents were shown to have remarkable effects on the Fe–O–Si interaction of precipitated Fe/Cu/K/SiO2 catalysts for low-temperature Fischer-Tropsch synthesis (FTS). With the increase in K content from 2.3% (100 g Fe based) up to 7% in the calcined precursors, Fe–O–Si interaction was weakened, as reflected by ATR/FTIR, H2-TPR and XPS investigations. XRD results confirmed that the diffraction peak intensity from (510) facet of χ-Fe5C2 phase strengthened with increasing K loading, which indicates the crystallite size of χ-Fe5C2 increased with the increase in K contents either during the syngas reduction/carburization procedure or after FTS reaction. H2-TPH results indicated that more reactive surface carbon (alpha-carbon) was obtained over the higher K samples pre-carburized by syngas. Raman spectra illustrated that a greater proportion of graphitic carbon was accumulated over the surface of spent samples with higher K loading. At the same time, ATR-FTIR, XRD and Mössbauer spectra (MES) characterization results showed that a relatively higher level of bulk phase Fayalite (Fe2SiO4) species was observed discernibly in the lowest K loading sample (2.3 K%) in this work. The catalytic evaluation results showed that the CO conversion, CO2 selectivity and O/P (C2–C4) ratio increased progressively with the increasing K loading, whereas a monotonic decline in both CO conversion and O/P (C2–C4) ratio was observed on the highest K loading sample during c.a. 280 h of TOS.

Microstructure and mechanical properties of Ti basic bionic gradient heterogeneous alloy prepared by multi-wire arc additive manufacturing

Inspired by biological gradient structure, Ti basic gradient heterogeneous alloy component from TC11 alloy to TC4 alloy was fabricated by multi-wire arc additive manufacturing (MWAAM). The chemical mixing, phase and microstructure evolution, microhardness distribution and tensile property of Ti basic gradient heterogeneous alloy were investigated through EDS, XRD, SEM, hardness tester and tensile tester. The results indicated that the alloy elements formed a long-distance gradient concentration distribution during the transition between two different titanium alloys due to dilution, remelting, and convective mixing in the molten pool. The intensity of diffraction peaks of Ti basic gradient heterogeneous alloy in the gradient region had no obvious change. The microstructure of MWAAM Ti basic gradient heterogeneous alloy was mainly consisted of lamellar αP, acicular αS, equiaxed αS and β matrix. Different morphology of the αS phase was mainly attributed to the wetting state of the second solid phase and grain boundary. In addition, the microstructure of α phase in Ti basic gradient heterogeneous alloy was significantly changed by the gradient distribution of alloy composition. The gradient heterogeneous alloy component manufactured in this work had high bonding strength. The average UTS of MWAAM Ti basic gradient heterogeneous alloy was 793.14 MPa, which was close to MWAAM TC4 alloy and reached approximately 85% of MWAAM TC11 alloy.

Durability of solidified sludge with composite rapid soil stabilizer under wetting–drying cycles

Composite rapid soil stabilizer (CRSS) comprising calcium sulfoaluminate cement, gypsum, lithium carbonate, and ionic soil stabilizer is characterized by rapid hardening and high strength. In this study, it was used to solidify sludge rapidly, and how the number of wetting–drying (WD) cycles and the CRSS dosage influenced the durability of the solidified sludge was studied. The results show that for a given CRSS dosage but an increasing number of WD cycles, the dry mass and density of the solidified sludge decreased, the water content and pH of the soaking solution increased, the unconfined compressive strength increased slightly, then decreased slowly, finally stabilized. The ettringite in the solidified sludge was transformed from columnar to needle-like. the diffraction peak intensity decreased, and the microscopic pores increased in both size and quantity. With increasing CRSS dosage, the apparent structure was more intact, the strength attenuation was smaller. After 12 WD cycles, with a 20% content of solidified sludge, the dry mass loss was only 2%, the strength loss was only 12%, and the cumulative pore volume did not increase obviously, which was maintained at about 0.20 ml/g, showing the high resistance to WD erosion. Based on the chemical reaction and combined with the macroscopic and microscopic test results, the microscopic evolution mechanism of the durability of solidified sludge under WD cycles—especially the strength evolution mechanism—is revealed clearly. The solidified sludge with CRSS had good durability against WD cycles, thereby laying a theoretical foundation for applications of CRSS.

Effect of the nickel molar content on the preparation and properties of spinel-type black ceramic pigment by microwave processing from stainless steelmaking dust

The transformation of stainless steel dust(SSD) rich in transition metal elements into Fe-Cr-Ni series spinel-type black ceramic pigment can solve a number of problems associated with traditional high-temperature SSD treatment while also maximizing resource efficiency and harmlessness utilization. Microwave heating and calcination at 900 °C using SSD, Cr2O3, and NiO as the main raw materials, altering the molar ratio of Fe and Cr in the raw materials to 1, and gradually adding NiO, were used to make black spinel ceramic pigments in this study. The solid solution phase is gradually replaced by the spinel phase as the amount of NiO added increases, and the primary phases are Ni(FeCr)O4 and NiCr2O4. The generated pigment phases are completely transformed to spinel when the Fe/Cr/Ni molar ratio is altered to 1:1:0.5. Because NiO can react with spinel in SSD, increasing the NiO content of the raw material will increase the intensity of the spinel phase diffraction peak. According to morphological examination, the prepared spinel pigments have a characteristic polyhedral shape. Furthermore, as the amount of NiO increases, so does the average grain size of the spinel phase, the orbital hybridization effect, the degree of atomic inversion in tetrahedra and octahedra, and oxygen vacancies and deficiencies, resulting in an increase in visible light absorbance and a decrease in band gap width. The prepared spinel pigments are fired in ceramics and exhibit good color rendering and adaptation properties.

Failure Analysis of a Chromium Plating Layer on a Piston Rod Surface and the Study of Ni-Based Composite Coating with Nb Addition by Laser Cladding

The failure of a chromium plating layer on the surface of a piston rod was analyzed, and an Ni-based alloy mixed with a niobium (Nb) composite coating was investigated by means of stereomicroscopy, metallographic microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Vickers hardness testing, and wear testing. The results show that penetrating cracks were present in the chromium layer. Subsequently, the corrosion intensified, resulting in the bubbling, cracking, and peeling of the chromium layer. The cladding layer presented a structure morphology of planar crystalline at the bottom, dendritic at the middle, and equiaxial crystalline at the top. The solidification parameters, which were derived from simulation results, confirmed that the ratios between temperature gradient (G) and solidification speed (S) decreased, and the values of the cooling speeds increased from the bottom to the top of the cladding layer. With an increase in Nb content, the structure became gradually refined and uniformly dense. The cladding layer of the Ni-based alloy mixed with Nb was mainly composed of γ-Ni, Cr23C6, Cr7C3, NbC, and Ni3Nb. NbC could be formed in situ and presented itself in four forms: particles, dendrites, polyhedrals, and networks. The microhardness of the coating with 15% added Nb was enhanced to 400 HV0.2, and the wear resistance thereof was 11.14 times higher than the substrate. After the 15% Nb coating had aged for 16 h, the diffraction peak intensities of Cr23C6 and Cr7C3 significantly increased, and the volume fraction of granular NbC increased from 1.67% to 2.54%. The microhardness was enhanced to 580 HV0.2, and the wear resistance thereof was better than that of the chromium plating layer.

Nonvolatile Memristive Devices Based on In Situ Functionalized Layered rGO-MoS2 Nanocomposites

Hybrid composites comprised of layered two-dimensional (2D) materials have attracted growing attention, especially in large-area electronics. Herein, we exploit the synergistic interfacial effect of molybdenum disulfide (MoS2) grafted reduced graphene oxide (rGO) and study the memristive characteristics of the layered hybrid rGO-MoS2 nanocomposites (NCs). The synthesized materials are analyzed using optical, structural, elemental, and morphological techniques. The average number of layers (∼6 to 10) is estimated from the intense X-ray diffraction peak of the polycrystalline materials. The intercalation of rGO in the rGO-MoS2 NCs results in an increased energy bandgap compared to pristine MoS2. The photoluminescence study exhibits dominant blue emission due to the restoration of the sp2-hybridized carbon domain in the reduced sheets. The surface topography of the NCs shows a 3D flower-like structure with multiple nano-petals interconnected in the form of nanosheets. The average diameter of the flower-shaped particles is calculated to be ∼258 and ∼301 nm for MoS2 and rGO-MoS2, respectively. The crossbar devices (ITO/rGO-MoS2/Cu) in a sandwich configuration (thickness ∼700 nm) are fabricated, displaying stable and repeatable bipolar resistive switching characteristics. The trapping and de-trapping of the charge carriers at the rich sulfur vacancies are responsible for bipolar memory behavior.

Effects of ZnO nanoparticle/nanorod composite films on the performance of organic solar cells

<p indent="0mm">In past decades, organic solar cells (OSCs) have attracted much attention due to their advantages such as light weight, flexibility, variable color, adjustable band gap and roll-to-roll (R2R) manufacturing. Recently, the certificated power conversion efficiency (PCE) of single-junction OSCs has exceeded 18%, showing great potential for commercial applications. The outstanding performance of OSCs strongly depends on innovative research on the synthesis of efficient active materials. However, essential interfacial modification is also very critical because it can not only benefit charge extraction and transportation, but also effectively protect the active materials and thus improving the device performance. Therefore, various interfacial materials have been investigated intensively for highly efficient OSCs. Zinc oxide (ZnO) nanomaterials with excellent optoelectronic properties are considered to be one of the most promising candidates for electron transport layers (ETLs) of R2R printed OSCs. However, ETLs of the most common ZnO nanoparticles (NPs) inevitably have plenty of surface defects due to their high surface to volume ratio, which impairs the carrier transportation and collection. To address this concern, in this work, a composite film of ETL is designed for OSCs using the mixture of ZnO nanorods (NRs) and ZnO NPs. ZnO NRs with hexagonal crystal structure are synthesized by the solvothermal method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The results show that the intensity of diffraction peak (002) of ZnO NRs was significantly higher than that of diffraction peak (101) and peak (101), indicating that nanorods grow along the <italic>c</italic>-axis orientation. It is also found that the diameter and length of well-crystallized ZnO NRs range from 5 to <sc>8 nm</sc> and from 15 to <sc>40 nm,</sc> respectively. The ZnO NRs are introduced as the electron transport material for OSCs with the structure of ITO/PEDOT:PSS/PM6:Y7/ZnO NPs/ZnO NPs:NRs/Al. The prepared ZnO NRs are blended with ZnO NPs to achieve an optimal surface morphology of the ETL and enhanced light capture capability of the device. ETLs with different ratios of ZnO NRs to ZnO NPs are prepared. When the mass ratio of ZnO NRs reaches 50%, the ETL becomes dense and uniform without apparent cracks and pinholes, so the resultant OSCs achieve the best performance. The best device shows a short circuit current density (<italic>J</italic>_sc)<italic> </italic>of <sc>24.30 mA cm^–2,</sc> an open circuit voltage (<italic>V</italic>_oc) of <sc>0.85 V,</sc> and a fill factor (FF) of 70.17%, corresponding to a champion PCE of 14.50%, which is higher than that of OSCs without ZnO NRs (PCE of 13.69% with <italic>J</italic>_sc<italic> </italic>of <sc>23.59 mA cm^–2, </sc><italic>V</italic>_oc<italic> </italic>of <sc>0.83 V</sc> and FF of 69.91%). Meanwhile, it is shown that the external quantum efficiency (EQE) curve of the optimal OSCs with ZnO NRs is higher than those of OSCs without ZnO NRs, which is consistent with the experimental results of <italic>J-V</italic> curve. The significant improvements attribute to the enhancement on the electron extraction and the light capture capability by the incorporation of ZnO NRs with excellent transport properties and the improved ETL morphology. Appropriately increased roughness after the incorporation of ZnO NRs also benefits the light absorption of the device. This work could come up with a new idea for the synthesis and application of ZnO-based interfacial materials in thin-film solar cells.

Quantitative phase analysis and rietveld texture determination of minerals in ash deposits in a 11.2 MW moving grate boiler

Some ash deposits were sampled from a 11.2 MW moving grate boiler to study the mineral transformation, ash deposition and mineral texture evolution behavior, which were determined by different analytical methods. Rietveld refinement was applied to determine the mineralogy, refine the crystallographic structures of minerals, and characterize texture heterogeneity of minerals in ash deposits. The results presented that the major mineral phases in ash deposits were identified as silicates, oxides, sulphates, sulfides and carbonates. The phase transformation between minerals during combustion was proposed. The variation of the diffraction peak intensities indicated the existence of the weak and strong textures. The texture indexes were larger than one mrd2 for most minerals, implying strong preferred orientation distributions, while the texture indexes of some other minerals were approaching one mrd2, indicating the existence of weak and random textures. Some pole figures showed strong texture features with a high degree of texture disorder in these minerals, while other minerals displayed weak textures with low volume diffractions of preferred orientations in these mineral phases. Owing to the diffraction peak overlapping of different minerals, different texture components with fibre-like or biaxial-like characteristics were found in ash deposits.

Starch propionylation acts as novel encapsulant for probiotic bacteria: A structural and functional analysis

Propionylated potato starch (PPS) with different degrees of substitution (DS) was prepared from native potato starch (NPS) and their potential to encapsulate Lactobacillus rhamnosus GG (LGG) was analyzed. Fourier transform infrared spectroscopy (FTIR) showed a characteristic peak of propionyl groups, which appeared at 1746 cm−1, demonstrating that propionylation occurred. X-ray diffraction (XRD) results revealed that the characteristic diffraction peak intensity of PPS gradually disappeared with the increasing of the DS, which was related to the loss of the ordered crystalline structure of starch granules. Propionylation resulted in the starch to be more thermally stable than its native starch. Furthermore, the propionylated starch had a higher resistance to digestion and hydrophobicity. More importantly, the micro-capsulated LGG derived from propionylated starch could achieve a maximum embedding efficiency of 87.77% at starch DS = 1.54, and also demonstrated a higher resistance to a strong acidic condition and a greater storage stability at 4 °C. This study may highlight a novel approach for probiotic encapsulation using propionylated potato starch as an encapsulant.

In situ X-ray diffraction analysis of electrochemical Dy–Ni alloying in molten LiCl–KCl

In situ energy-dispersive X-ray diffraction was employed to investigate electrochemical Dy–Ni alloying in molten LiCl–KCl at 723 K. This enabled the determination of the crystal structures and orientations of the products formed during molten salt electrolysis, while also eliminating the effects of the post-electrolysis processes (such as cooling and washing) that are necessary in ex situ measurements. The diffraction peak intensities of DyNi2 generally increased during potentiostatic electrolysis at 0.50 V vs. Li+/Li, whereas the Ni diffraction peak intensities gradually decreased. Furthermore, the intensity of the X-ray fluorescence peak of Dy gradually increased. Thus, DyNi2 could be directly formed from Ni via electrolysis, as no diffraction peaks corresponding to materials other than Ni and DyNi2 were observed. Moreover, (022)-oriented DyNi2 grew preferentially on the (200)-oriented Ni substrate.

Comparison of structural and functional properties of maize starch produced with commercial or endogenous enzymes

To explore an effective and economic method to prepare higher contents of resistant starch (RS), different enzyme treatments including single pullulanase (PUL), commercial α-amylase (AA) or/and β-amylase (BA) with PUL, and malt endogenous amylase (MA) with PUL were used and the structural, physicochemical properties and digestibility of all modified starches (MS) were compared. All the enzyme-treated starches displayed a mixture of B and V-type diffraction patterns. The MA/PUL-MS showed higher V-type diffraction peak intensity as compared to other modified starches. Compared to the combination of commercial enzyme treatment, the combination of malt enzyme treatment led to higher apparent amylose contents (45.56%), RS content (53.93%) and thermal stability (302 °C), whereas it possessed lower solubility indices and predicted glycaemic index. The apparent viscosity and shear resistance of MA/PUL-MS were lower than that of AA/PUL-MS, whereas that of MA/PUL-MS was higher than that of BA/PUL-MS and BA/AA/PUL-MS. These findings would provide a theoretical and applicative basis to produce foods with lower GI in industrial production.

Effect of Fermentation Time on Molecular Structure and Physicochemical Properties of Corn Ballast Starch.

The effect of fermentation treatment on the surface morphology, crystal structure, molecular weight, chain length distribution, and physicochemical properties of corn starch was investigated using natural fermentation of corn ballast. The amylose content in corn ballast starch reduced at first after natural fermentation, then grew, following the same trend as solubility. There were certain erosion marks on the surfaces of fermented corn ballast starch granules. The crystalline structure of corn ballast starch remained the same, i.e., a typical A-type crystalline structure, at different fermentation times; however, the intensities of diffraction peaks were different. The weight-average molecular weight of starch first increased and then decreased after fermentation. The content of low-molecular-weight starch (peak 3) decreased from 25.59 to 24.7% and then increased to 25.76%, while the content of high-molecular-weight starch (peak 1) increased from 51.45 to 53.26%, and then decreased to 52.52%. The fermentation time showed a negative correlation with the viscosity of starch, and the pasting temperature first increased, and then decreased. Natural fermentation can be used as a technical means to produce corn starch products as a result of the experiments' findings, and future experiments will detect and analyze the bacterial structure of corn fermentation broth in order to better understand the molecular mechanism of natural fermentation affecting the structure and physicochemical properties of corn starch.

Surface Debye temperature determination from LEED: correlation to defects in epitaxial films

Low energy electron diffraction (LEED) peak intensities were measured to estimate surface Debye temperature for epitaxially-grown silicon thin films and for bulk Si (001). Rutherford backscattering spectroscopy (RBS, random and channeling modes) and positron annihilation spectroscopy (PAS) were used to quantify defect density and distribution in the near-surface layers. The surface Debye temperature of bulk Si (001), and 1.0 μm, and 0.6 μm Si on sapphire were measured to be 333 K, 299 K, and 260 K, respectively. RBS and PAS showed that the defect concentration was highest near the film/substrate interface, presumably due to the lattice mismatch, and decreased toward the top surface. The thicker film presented fewer defects in the surface and near-surface layers. We showed that a larger concentration of defects Nd in Si epitaxial films correlates with a lower surface Debye temperature following the empirical relation θD=(365±14)−(8.1±1.5)×10−13Nd for our set of samples. Our study suggests the further development of LEED to estimate near-surface defect concentrations.

Growth of high material quality InAs/GaSb type-II superlattice for long-wavelength infrared range by molecular beam epitaxy

By optimizing the V/III beam-equivalent pressure ratio, a high-quality InAs/GaSb type-II superlattice material for the long-wavelength infrared (LWIR) range is achieved by molecular beam epitaxy (MBE). High-resolution x-ray diffraction (HRXRD), atomic force microscopy (AFM), and Fourier transform infrared (FTIR) spectrometer are used to characterize the material growth quality. The results show that the full width at half maximum (FWHM) of the superlattice zero-order diffraction peak, the mismatching of the superlattice zero-order diffraction peak between the substrate diffraction peaks, and the surface roughness get the best results when the beam-equivalent pressure (BEP) ratio reaches the optimal value, which are 28 arcsec, 13 arcsec, and 1.63 Å, respectively. The intensity of the zero-order diffraction peak is strongest at the optimal value. The relative spectral response of the LWIR detector shows that it exhibits a 100% cut-off wavelength of 12.6 μm at 77 K. High-quality epitaxial materials have laid a good foundation for preparing high-performance LWIR detector.

Sintering characteristic, structure, microwave dielectric properties, and compatibility with Ag of novel 3MgO-B2O3-xwt% BaCu(B2O5)-ywt% H3BO3 ceramics

ABSTRACT In this study, 3MgO-B2O3-xwt%BaCu(B2O5) (BCB)-ywt%H3BO3 (2 ≤ x ≤ 8, 0 ≤ y ≤ 20) ceramics were sintered at the optimum temperature to form Mg3B2O6 and MgO phases. The effects of H3BO3 and BCB on the product characteristics, phase transition, microstructure, and microwave dielectric properties of 3MgO-B2O3 ceramics were investigated. The intensities of diffraction peaks of two phases varied with changing the x and y values. After sintering at 950°C, the ceramics with x = 6 and y = 15 achieved the excellent microwave properties with a εr of 6.72, Q × f of 83,205 GHz and τf of – 65.05 ppm/°C. Besides, the ceramics with x = 8 and y = 5 sintered at 925°C also achieved good microwave dielectric properties with a εr of 6.64, Q × f of 78,173 GHz and τf of – 57.27 ppm/°C. The sintering temperatures of above both ceramics are well lower than the melting point of Ag, showing promising applications in low temperature cofired ceramic devices. In particular, these two ceramics can be used as the potential candidate materials for microwave ceramics for 5 G technology, provided that τf can be further optimized.

Structural, optical, and dielectric modulus properties of PEO/PVA blend filled with metakaolin

The PEO/PVA blend incorporated by different weight percentages (≤10%) of metakaolin (MK) has been prepared and characterised. The XRD revealed a semicrystalline structure of pure PEO/PVA with peaks indicating the presence of silicon and aluminum in the MK composition. The addition of MK in the blend leads to a decrease in the diffraction peak intensities, confirming that the blend-MK interactions break some PEO/PVA blend domains. The UV–Vis transmittance and reflectance spectra were studied and used to determine optical parameters. The decrease in the band-gap values was demonstrated with the increase in MK to confirm the suitability of MK as a band-gap regulated the optical material in different applications. The obtained values of the optical band gap decrease with the increase of MK concentration due to the defect levels that correlate to the sample's density of localized states. The higher values of ε′ found at a lower frequency related to the effect of the dominant contribution of the interfacial polarization due to the accumulation of charges, whereas the higher values of ε″ at the lower frequency were related to an increase in the energy loss in the composite films. The Cole-Cole plot displays semicircles at the lower frequency range with a linear increase at the intermediate and higher frequency due to the grain boundary and the relaxation process. The values of the real part (σ′) are lower than that of the corresponding values of the imaginary part (σ″). Applied an electric field causes polarized films and the ability to store an electric charge. Therefore, these composites may be used in flexible capacitors.