Characterization Of Property Research Articles

Synthesis and Characterizations of Structural, Dielectric and Optical Properties of CCTO– PT Composite

In this study, we have synthesized the (1-x) CaCu3Ti4O12 – (x) PbTiO3 (CCTO-PT) composites with x = 0.00, 0.50 and 1.00 by using the solid-state method. We have then studied the structural, optical and dielectric properties of these composites. The X-ray diffraction diffractogram (XRD) showed that the ceramics at x = 0.00 and 1.00 (CCTO and PT) crystalize in a pure cubic and tetragonal phase respectively. Likewise, for CCTO-PT composite, we observed a coexistence of tetragonal and cubic phase in CCTO-PT composite composites. The scanning electron microscopy (SEM) micrographs showed homogeneous microstructure samples and consist of different grain shape. The large spherical grain structure is attributed to CCTO ceramic while the smaller grain form can be ascribed to the PT ceramic. The dielectric measurements results revealed an increase in dielectric permittivity value for CCTO-PT composite compared with pure CCTO and PT. The optical band gaps of the CCTO and PT are 2.50 and 3.00 eV, and increased to 3.50 eV for the CCTO/PT composite.

In-situ grown MXene@PDA/MOF composites constructed electrochemical sensor for detecting trace l-cysteine

In this study, novel honeycomb-like morphology MXene@PDA/MOF composites were prepared in situ on the surface of MXene@PDA (polydopamine), combined with 2-methylimidazole and Zn2+. The characterizations of morphology and electrochemical properties show that MXene@PDA/MOF has large specific surface areas and outstanding electroconductibility. Furthermore, the MXene@PDA/MOF-based sensor was fabricated to detect l-cysteine (L-Cys). The response of differential pulse voltammetry (DPV) shows the current intensity increases as l-Cys concentration. Under the optimum conditions, DPV response shows a fine linear relationship with l-Cys concentration in a range of 0.01 – 5.0 μmol L−1 with the detection limit of 3.74 × 10−9 mol L−1. This sensor was used to detect l-Cys in real samples with recoveries of 100.34 % – 101.68 %. Thus, the MXene@PDA/MOF-based electrochemical sensor exhibits excellent selectivity, reproducibility, stability, and practicability.

Tunable Properties of New Cyano‐Substituent Heptahelicenes for Optoelectronic Devices: A Combined Experimental and DFT Computational Study

AbstractHere, we describe a set of coupled experimental and theoretical analyses. The introduction of one and two additional cyano groups in the carboheptahelicene backbone enhance its electron‐accepting properties. New carboheptahelicene derivatives are synthesized, and relevant characterizations of structural features, photophysical and electrochemical properties, and structure‐property relationships are described. This present work concerns the use of the density functional theory (DFT) to highlight the structural and the optoelectronic properties of carboheptahelicene derivatives and comparing the obtained findings with the experimental ones. The experimental and theoretical spectra (UV‐Vis absorption and photoluminescence) provide excellent concurrence. Afterward, molecular structures, structural parameters, molecular electrostatic potential (MEP), highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies of frontier molecular orbitals (FMOs) are constructed. Some other optoelectronic parameter including electron affinity (EA), ionization potential (IP), and some reactive descriptor such as chemical potential (μ), global hardness (η), electronegativity (χ) and the overall electrophilicity index (ω) are determined and indicating its potential uses as an active layer in optoelectronic efficient devices. The topological methods such as electron localization function (ELF), localization orbital locator (LOL) and the reduced density gradient method (RDG) were also conducted to clarify the strengths and kinds of interactions.

The approximation property for the predual of weighted spaces of holomorphic mappings on Banach spaces

In this paper, we investigate the approximation property for the predual of the weighted space of holomorphic mappings, where is a countable family of weights defined on a balanced open subset U of a Banach space E. We introduce a locally convex topology on and show that is topologically isomorphic to for a suitably restricted family . As a consequence, certain characterizations of the approximation property for the space are proved.

Promoting surface lattice oxygen and oxygen vacancy of CeO2 for photothermal methane dry reforming over Ni/CeO2 catalysts

The ever-increasing concentrations of CH4 and CO2 result in the greenhouse effect around the world. It’s meaningful to transform the gases for environment protection. In this work, we studied photothermal methane dry reforming over Ni/CeO2 catalysts by shaping CeO2 to nanorods and nanosheets, converting the greenhouse gases to syngas and trying to resolve challenges of Ni sintering and carbon deposition in the reaction. Through characterizations of physicochemical and optical properties, the surface lattice oxygen and oxygen vacancy were verified being more promoted on the nanorods catalysts than on the nanosheets catalysts, giving the greater reforming performance. The irradiation of visible-light accelerated CH4/CO2 rates, which was originated from that the photoelectrons reduced CO2 and the holes oxidized CHx. The oxygen vacancy strengthened metal-support interaction limiting Ni sintering, and the surface lattice oxygen gasified carbon precursors decreasing carbon deposition. The synergism between thermocatalysis and photocatalysis on the optimized 5Ni/CeO2 nanorod catalyst contributed to CH4 and CO2 rates up to 204 μmol/(gcats) and 245 μmol/(gcats), respectively, at 973 K, and carbon deposition less than 0.5 wt%. These were much superior to most reported performance. The work provided a novel photothermal approach for significantly decreasing carbon deposition in methane dry reforming.

Propagation of distinct CWD prion strains during peripheral and intracerebral challenges of gene-targeted mice

Since prion diseases result from infection and neurodegeneration of the central nervous system (CNS), experimental characterizations of prion strain properties customarily rely on the outcomes of intracerebral challenges. However, natural transmission of certain prions, including those causing chronic wasting disease (CWD) in elk and deer, depends on propagation in peripheral host compartments prior to CNS infection. Using gene-targeted GtE and GtQ mice, which accurately control cellular elk or deer PrP expression, we assessed the impact that peripheral or intracerebral exposures play on CWD prion strain propagation and resulting CNS abnormalities. Whereas oral and intraperitoneal transmissions produced identical neuropathological outcomes in GtE and GtQ mice and preserved the naturally convergent conformations of elk and deer CWD prions, intracerebral transmissions generated CNS prion strains with divergent biochemical properties in GtE and GtQ mice that were changed compared to their native counterparts. While CWD replication kinetics remained constant during iterative peripheral transmissions and brain titers reflected those found in native hosts, serial intracerebral transmissions produced 10-fold higher prion titers and accelerated incubation times. Our demonstration that peripherally and intracerebrally challenged Gt mice develop dissimilar CNS diseases which result from the propagation of distinct CWD prion strains points to the involvement of tissue-specific cofactors during strain selection in different host compartments. Since peripheral transmissions preserved the natural features of elk and deer prions, whereas intracerebral propagation produced divergent strains, our findings illustrate the importance of experimental characterizations using hosts that not only abrogate species barriers but also accurately recapitulate natural transmission routes of native strains.

Exploring the Therapeutic Potential of 5-Fluorouracil-Loaded Calcium Carbonate Nanoparticles Combined with Natural Compound Thymoquinone for Colon Cancer Treatment.

Given the need for novel and effective therapies for colon cancer, this study aimed to investigate the effects of 5-fluorouracil-loaded calcium carbonate nanoparticles (5FU-CaCO3np) combined with thymoquinone (TQ) against colon cancer. A shaking incubator and a high-speed homogenizer were used to prepare the optimal 5FU-CaCO3np, with characterizations of physicochemical properties, in vitro drug release profile, and biocompatibility. In vitro experiments and molecular docking were employed to evaluate the therapeutic potential of the combination for colon cancer treatment. Study results revealed that 5FU-CaCO3np with a size of approximately 130 nm was synthesized using the high-speed homogenizer. Its favorable biocompatibility, pH sensitivity, and sustained release properties facilitated reduced toxic side effects of 5-FU on NIH3T3 normal cells and enhanced inhibitory effects on CT26 colon cancer cells. The combination of 5FU-CaCO3np (1.875 μM) and TQ (30 μM) showed significantly superior anti-colon cancer effects to 5FU-CaCO3np alone in terms of cell proliferation and migration inhibition, cell apoptosis induction, and spheroid growth suppression in CT26 cells (p < 0.05), with strong interactions between the drugs and targets (E-cadherin, Bcl-2, PCNA, and MMP-2). These results provide evidence for 5FU-CaCO3np as a novel regimen against colon cancer. Combining 5FU-CaCO3np and TQ may offer a new perspective for colon cancer therapy.

Characterization of Composite Film Containing Polyvinyl Alcohol Cross‐Linked With Dialdehyde Cellulose Using Citric Acid as a Catalyst for Sustainable Packaging

ABSTRACTThis study is aimed at fabricating composite films by cross‐linking polyvinyl alcohol (PVA) and dialdehyde cellulose (DAC) in varying ratios using citric acid as a catalyst. The acetal formation between the two components was studied using FTIR. Characterizations of the physiochemical properties revealed that increasing the DAC ratio of the composite film improved the hydrophobicity, tensile strength and barrier properties (water vapour, UV and oxygen) of the films while reducing elongation at break (flexibility), swelling and solubility of the film in water. When the DAC ratio was elevated to 50%, the tensile strength was enhanced to 98 MPa. In comparison, flexibility diminished to 29%, the solubility of the film reduced to 10% and water vapour permeability was lower by two orders of magnitude than that of the control PVA film. The peroxide value of linoleic acid decreased from 21.2% ± 7.6 (packed with PVA film) to 9.9% ± 0.9 (packed with 50% DAC composite film) after 15 days. Furthermore, the composite films demonstrated effective absorption of UV radiation, with the order of effectiveness being UV‐C &gt; UV‐B &gt; UV‐A radiation. No significant difference in biodegradability was detected in the composite films with an increase in DAC ratio during indoor soil burial tests for 30 days. This study implies that the composite film could serve as an alternative sustainable packaging option, especially when transparency and high oxygen barrier properties are desired.

New Solitary Waves for Thin-Film Ferroelectric Material Equation Arising in Dielectric Materials

Abstract In this paper, the thin-film ferroelectric material equation (TFFME), which enables the propagation of solitary polarisation in thin-film ferroelectric materials is investigated, will be expressed through the non-linear evolution models. Ferroelectrics are dielectric materials that explain wave propagation non-linear demeanors. The non-linear wave propagation form is administrated by TFFME. To investigate the characterisations of new waves and solitonic properties of the TFFME, the modified exponential Jacobi technique and rational exp(−ϕ(η))-expansion technique are used. Plenty of alternative responses may be achieved by employing individual formulas; each of these solutions is offered by some plain graphs. The validity of such schemes and solutions may be exhibited by assessing how well the relevant schemes and solutions match up. The effect of the free variables on the manner of acting of reached plots to a few solutions in the exact forms was also explored depending upon the nature of non-linearities. The descriptive characteristics of the reached results are presented and analysed by some density, two- and three-dimensional figures. We believe that our results would pave the way for future research generating optical memories based on non-linear solitons.

Topological boundaries of representations and coideals

For a locally compact quantum group G, a (left) coideal is a (left) G-invariant von Neumann subalgebra of L∞(G). We introduce and analyze various generalizations of amenability and coamenability to coideals of discrete and compact quantum groups. We focus on a particular class of coideals found in the category of compact quantum groups, which are associated with a compact quasi-subgroup. This class includes all coideals of the quotient type. We also introduce the notion of a Furstenberg-Hamana boundary for representations of discrete quantum groups and use it to study amenability and coamenability properties of coideals. We then prove that a coideal of a compact quantum group that is associated with a compact quasi-subgroup is coamenable if and only if its codual coideal is G-injective. If G is a unimodular or an exact discrete quantum group, we can replace G-injectivity in the latter statement with the weaker condition of relative amenability. This result leads to a complete characterization of the unique trace property. Specifically, a unimodular discrete quantum group G has the unique trace property if and only if the action of G on its noncommutative Furstenberg boundary is faithful. We also demonstrated that if a unimodular discrete quantum group G is C⁎-simple then it has the unique trace property. These findings are the quantum analogs of the groundbreaking results of Breuillard, Kalantar, Kennedy, and Ozawa and they provide answers to questions posted by Kalantar, Kasprzak, Skalski, and Vergnioux.

Preparation and mechanical characterization of natural polymer composite material obtained from fox tail palm seeds

This experimental investigation reveals the preparation of natural composite material from foxtail palm tree seeds. The fruits from the foxtail palm tree are used for the extraction of oil, and the by-product of the extraction process is freely dumped. This study attempts to utilize the waste by-product of foxtail palm tree fruit as a valuable natural composite material. The fabrication was done using the hand lay-up method for the proposed reinforcement (4% and 8%) of filler materials. The obtained composite materials are subjected to significant mechanical characterization of tensile behaviour, flexural property, and hardness. In addition, the morphological study was also carried out by the scanning electron microscope (SEM). The results show that, as the reinforcement percentages of filler material increase, the mechanical properties are improved. This may be due to the uniform dispersion of natural fibres in the polymer. The tensile strength was improved by 22.43% and 29.08% for 4% and 8% filler reinforcement. Similarly, the stiffness property was improved by 9.32% for 4% reinforcement and 18.68% for 8% reinforcement when compared with neat composite. The SEM images reveal the failure analysis, bonding strength and fibre pull-out in the composites. Finally, the foxtail fruit fibre shows promise as a reinforcing agent in composite materials, improving their mechanical properties and making them suitable for various applications requiring strength, stiffness, and resistance to deformation.

Multiscale characterization of effective mechanical properties of graphene-chitosan composite aerogels

This work reports on numerical characterizations of effective mechanical properties associated with graphene-polymer composite aerogels produced using an environmentally friendly freeze-drying process. To this purpose, a multiscale approach was implemented, in which geometrical configurations were constructed based on the results of experimental characterizations. A homogenization procedure based on molecular mechanics, the Milton method, and the asymptotic homogenization method was applied. In the asymptotic homogenization method, cell problems were formulated and solved within a representative volume element using the finite element method. After validating the numerical model through experimental results from compression tests, a parametric study on the influence of microstructural parameters of the materials, such as dispersion state, aspect ratio, volume fraction of nanoinclusions, and material porosity, on the macroscopic mechanical behavior of the composite aerogels was conducted. The simulation results provided a deeper understanding of the mechanisms that enhanced the mechanical properties of such aerogels by adding various graphene derivatives, allowing for adjustments in the elaboration process to obtain materials with improved mechanical properties.

Synthesis, characterization and study of magnetic property of two isomorphic Cu(II) coordination polymers (CP) with chromone based ligand systems

Synthesis, characterization and magnetic properties of two Cu(II)-based coordination polymers (CPs, [{Cu(L1)(N(CN)2)}(ClO4)]n L1 = 3-(((2-(diethylamino)ethyl)imino)methyl)-4H-chromen-4-one (1) and [{Cu(L2)(N(CN)2)}(ClO4)]n L2 = 3-(((2-(dimethylamino)ethyl)imino)methyl)-4H-chromen-4-one (2)) involving chromone based chelating ligands and dicyanamide bridging ligands are reported. Both compounds have been characterized by physicochemical methods and the crystal structures have been determined by X-ray diffraction analysis, disclosing that they are isostructural and isomorphous compounds of polymeric linear chains where the central metal has adopted distorted square pyramidal coordination geometry. The magnetic studies reveal that the synthesized compounds show a prevailing paramagnetic behavior. Only below 15 K does a weak antiferromagnetic interaction become effective in these systems, and they have been further analyzed and interpreted.

Eventual concavity properties of the heat flow

The eventual concavity properties are useful to characterize geometric properties of the final state of solutions to parabolic equations. In this paper we give characterizations of the eventual concavity properties of the heat flow for nonnegative, bounded measurable initial functions with compact support.

Detailed characterizations of proton permeability properties through commercial Nafion® films under various acidic electrolytes

Nafion® film has been widely used as a representative cationic ion exchange membrane for electrochemical systems including water splitting. However, detailed H+ permeability properties have been poorly understood thus far. We here attempt to relate the H+ permeability with the material properties of Nafion® films. For that, four samples representing two casting types were selected to study the H+ permeability. We conducted the pretreatment to see the effect of the new alignment of the water clusters on the H+ permeability. Although the studied membranes show individual transport features, we observed the increased H+ permeability from 0.05 to 0.5 M concentrations in acidic electrolytes. Such a feature is caused by the increased chemical-potential gradient along with the osmotic de-swelling. We also found that a H+ diffusion channel is associated with the ionic cluster size of the films, which can explain the higher H+ permeability after the pretreatment. Lastly, the individual H+ permeability was obtained when measuring at different electrolytes, revealing that the H+ permeability is strongly influenced by the anionic mobility rather than the acidic dissociation constants. Our results provide a fundamental understanding of the H+ transports through the commercial Nafion® membrane, which gives a guideline for the rational design of ion exchange membranes.

On the derived numbers of a real function

The derived numbers of a real function at a point of its domain provide useful information about the variation of the function around that point. In this note, we introduce the concept of one-sided derived numbers and we obtain specific characterizations of some functional properties. We exemplify the usefulness of our results through some interesting consequences and applications.

A novel iron metal organic framework-based nanocomposite for the synergistic degradation and adsorption of organic pollutants and Cr (Ⅵ) under visible light

In this work, a novel nitrogenous Fe-TPPE metal-organic-framework (MOF) with excellent visible light catalytic activity was successfully prepared, and a magnetic composite (Fe3O4@Fe-TPPE) with Z-type heterojunction structure was designed to synergistically treat organic pollutants and Cr(Ⅵ). The materials were carefully characterized by powder X-ray diffractometry, scanning electron microscope, Fourier transform infrared analysis, UV–visible diffuse reflectance spectra, X-ray photoelectron spectroscopy, thermogravimetric analysis, etc. The characterizations of photoelectric properties showed that the novel Fe-TPPE MOF exhibited strong response to visible light and Fe3O4@Fe-TPPE had even stronger response. Furthermore, the adsorption and photocatalytic degradation capabilities of Fe-TPPE and Fe3O4@Fe-TPPE, and the versatility as photocatalysts for aqueous pollutants were assessed through removal studies of the model pollutants tetracycline, rhodamine, methyl blue and Cr (VI). Additionally, the removal mechanism of the Fe3O4@Fe-TPPE for the above pollutants was explored. The high removal efficiency, fast magnetic separation, great recycling stability and minimal leak during application all demonstrate the good potential of Fe3O4@Fe-TPPE for practical and sustainable treatment of aqueous pollutants.

NMR characterization of RNA binding property of the DEAD-box RNA helicase DDX3X and its implications for helicase activity

The DEAD-box RNA helicase (DDX) plays a central role in many aspects of RNA metabolism by remodeling the defined structure of RNA molecules. While a number of structural studies have revealed the atomistic details of the interaction between DDX and RNA ligands, the molecular mechanism of how this molecule unwinds a structured RNA into an unstructured single-stranded RNA (ssRNA) has largely remained elusive. This is due to challenges in structurally characterizing the unwinding intermediate state and the lack of thermodynamic details underlying this process. In this study, we use solution nuclear magnetic resonance (NMR) spectroscopy to characterize the interaction of human DDX3X, a member of the DDX family, with various RNA ligands. Our results show that the inherent binding affinity of DDX3X for ssRNA is significantly higher than that for structured RNA elements. This preferential binding, accompanied by the formation of a domain-closed conformation in complex with ssRNA, effectively stabilizes the denatured ssRNA state and thus underlies the unwinding activity of DDX3X. Our results provide a thermodynamic and structural basis for the DDX function, whereby DDX can recognize and remodel a distinct set of structured RNAs to participate in a wide range of physiological processes.

A new method for investigating the impact of temperature on in-situ reservoir properties using high-temperature AFM

Accurately evaluating the influence of temperature variations is crucial for geothermal engineering. Existing conventional testing methods are limited in providing detailed characterizations of reservoir micro properties at high temperatures. This study employed variable-temperature AFM testing techniques to examine sandstone and limestone under in-situ temperatures (25-200°C). The study analyzed the mechanisms behind the temperature effects on rock properties and established theoretical models for porosity and permeability variations with elevated temperatures based on these mechanisms. The research revealed that sandstone and limestone exhibit similar temperature effects at high temperatures. The pore fractal dimension of sandstone and limestone does not change with temperature change. As the temperature increases, sandstone and limestone experience mean roughness (Ra) and porosity reductions. The impact of high temperature was more pronounced on sandstone compared to limestone, with sandstone showing a decrease of 2.8 % and 0.59 % in mean roughness (Ra) and AFM porosity, respectively, from 25 °C to 200 °C, while limestone exhibited reductions of 1.4 % and 0.085 %, respectively. With increasing temperature, sandstone transformed some pores with equivalent diameters of 1-2.5 μm to pores smaller than 1μm, while limestone did not show significant changes in pore structure. The temperature effects on sandstone and limestone were attributed to mineral expansion. Sandstone contains a higher proportion of minerals with a high coefficient of thermal expansion, such as quartz. In contrast, limestone primarily comprises minerals with lower thermal expansion coefficients, such as calcite, resulting in a more significant temperature impact on sandstone than on limestone. The theoretical models based on the mechanisms for porosity and permeability at high temperatures exhibited good predictive performance for sandstone and are more suitable for reservoirs predominantly composed of minerals with high coefficients of thermal expansion. The variation of porosity and permeability at high temperatures have different impacts on geothermal reservoirs. Temperature effects on porosity and permeability should be considered in geothermal engineering.

Shear Bond Strength to Enamel, Mechanical Properties and Cellular Studies of Fiber-Reinforced Composites Modified by Depositing SiO2 Nanofilms on Quartz Fibers via Atomic Layer Deposition.

Poor interfacial bonding between the fibers and resin matrix in fiber-reinforced composites (FRCs) is a significant drawback of the composites. To enhance the mechanical properties of FRC, fibers were modified by depositing SiO2 nanofilms via the atomic layer deposition (ALD) technique. This study aims to evaluate the effect of ALD treatment of the fibers on the mechanical properties of the FRCs. The quartz fibers were modified by depositing different cycles (50, 100, 200, and 400) of SiO2 nanofilms via the ALD technique and FRCs were proposed from the modified fibers. The morphologies, surface characterizations of nanofilms, mechanical properties, and cytocompatibility of FRCs were systematically investigated. Moreover, the shear bond strength (SBS) of FRCs to human enamel was also evaluated. The SEM and SE results showed that the ALD-deposited SiO2 nanofilms have good conformality and homogeneity. According to the results of FTIR and TGA, SiO2 nanofilms and quartz fiber surfaces had good chemical combinations. Three-point bending tests with FRCs showed that the deposited SiO2 nanofilms effectively improved FRCs' strength and Group D underwent 100 deposition cycles and had the highest flexural strength before and after aging. Furthermore, the strength of the FRCs demonstrated a crescendo-decrescendo tendency with SiO2 nanofilm thickness increasing. The SBS results also showed that Group D had outstanding performance. Moreover, the results of cytotoxicity experiments such as cck8, LDH and Elisa, etc., showed that the FRCs have good cytocompatibility. Changing the number of ALD reaction cycles affects the mechanical properties of FRCs, which may be related to the stress relaxation and fracture between SiO2 nanofilm layers and the built-up internal stresses in the nanofilms. Eventually, the SiO2 nanofilms could enhance the FRCs' mechanical properties and performance to enamel by improving the interfacial bonding strength, and have good cytocompatibility.