X-ray Diffraction Results Research Articles

Isolation and Characterization of Novel Cellulose Micro/Nanofibers from Lygeum spartum Through a Chemo-Mechanical Process

Recent studies have focused on the development of bio-based products from sustainable resources using green extraction approaches, especially nanocellulose, an emerging nanoparticle with impressive properties and multiple applications. Despite the various sources of cellulose nanofibers, the search for alternative resources that replace wood, such as Lygeum spartum, a fast-growing Mediterranean plant, is crucial. It has not been previously investigated as a potential source of nanocellulose. This study investigates the extraction of novel cellulose micro/nanofibers from Lygeum spartum using a two-step method, including both alkali and mechanical treatment as post-treatment with ultrasound, as well as homogenization using water and dilute alkali solution as a solvent. To determine the structural properties of CNFs, a series of characterization techniques was applied. A significant correlation was observed between the Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) results. The FTIR results revealed the elimination of amorphous regions and an increase in the energy of the H-bonding modes, while the XRD results showed that the crystal structure of micro/nanofibers was preserved during the process. In addition, they indicated an increase in the crystallinity index obtained with both methods (deconvolution and Segal). Thermal analysis based on thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) confirmed improvement in the thermal properties of the isolated micro/nanofibers. The temperatures of maximum degradation were 335 °C and 347 °C. Morphological analysis using a scanning electron microscope (SEM) and atomic force microscope (AFM) showed the formation of fibers along the axis, with rough and porous surfaces. The findings indicate the potential of Lygeum spartum as a source for producing high-quality micro/nanofibers. A future direction of study is to use the cellulose micro/nanofibers as additives in recycled paper and to evaluate the mechanical properties of the paper sheets, as well as investigate their use in smart paper.

A novel route of carburizing through microwave hybrid heating

Abstract Carburizing is a surface treatment process by diffusing carbon into the steel. These days, manufacturing industries demand highly efficient processes that consume low power. Microwave processing is a newly evolving process that consumes low power. This study proposes a novel route for carburizing mild steel (substrate) through experimental and simulation studies using a microwave heating. Charcoal powder was used as a susceptor to convert microwave energy into heat energy and to deposit carbon on the surface of the specimen. The mild steel specimens were exposed to the microwave power input of 900 W and 360 W for exposure time of 1500 s and 1980 s naming it as S2 and S3 respectively. The microstructural analysis of specimens S2 and S3 confirms the formation of pearlite structures at the surface. However, the amount of pearlite structure was significantly higher for the S3. The higher carbon content is confirmed through energy-dispersive x-ray spectroscopy (EDS) analysis of specimen S3. The average hardness of the S3 specimen was determined to be 220.8 HV, which shows an increase of 38.36% compared to the S1 (base metal). x-ray diffraction (XRD) results indicate the additional cementite peaks (Fe3C) and ferrite-confirming phase transformations for carburized samples. The wear analysis of S2 and S3 was conducted through pin-on-disk testing. The peak COF of 0.73 and 0.64 was observed for S2 and S3 respectively. The hard surface of S3 resists the penetration of the counter body to a greater extent due to the fine morphology of pearlite. From the FEM study, the maximum value of 7.96 × 10 3 (V/m) was determined at the center region for the electric field distribution in the microwave cavity, which is the optimum value for efficient heating. The maximum temperature of the mild steel obtained during the carburization process was 900 °C in 1800 s. The microwave carburizing process requires relatively less time than the conventional carburizing process which will save energy consumption.

Glucono-δ-lactone induced Auricularia auricula polysaccharide-casein composite gels for curcumin loading and delivery

Polysaccharides could be used to form the network structure of casein (CA) gel, and affect its gelling properties. Auricularia auricula polysaccharide (AAP) has good gel properties and activity, however, how the AAP affects gelling properties of CA gels remains unclear. In this study, AAP and CA were acid-induced by glucono-δ-lactone (GDL) to prepare composite gels for curcumin loading. The effects of different AAP additions on the gel structure were emphasized. Water holding capacity, rheology, texture profile analysis, sulfhydryl content, surface hydrophobicity and gel microstructure showed that the composite gels were most structurally stable upon addition of 0.4 % AAP. The composite gels exhibited a higher strength and a more regular network structure compared to the CA gels. The results of turbidity studies showed that CA and AAP formed gels through electrostatic interactions due to pH < pI. The results of FT-IR, X-ray diffraction, fluorescence spectroscopy, and UV–Vis spectroscopy indicated that curcumin interacted with the CA and was successfully encapsulated within the gel. In addition, in vitro simulated digestion experiments demonstrated that the composite gels exhibited better protection against curcumin than the single CA gel. The results suggested that composite gels can be used as a curcumin carrier, which may enhance its wider application in the food and health industries.

X-RAY SPECTROSCOPY OF SILICON DOPED WITH GERMANIUM ATOMS

This paper presents X-ray diffraction results of p-Si doped with germanium and tin atoms. It was found that after heat treatment of the initial silicon sample at a temperature of 1100°C, a new energetically favorable direction of crystallites appears. It was determined that germanium and silicon atoms form bonds in high-potential regions of the silicon crystal lattice and this leads to a deterioration in its monocrystallinity, that is, to an increase in the number of polycrystalline regions. It has been discovered that tin atoms in silicon combine with oxygen atoms and form SnO2 crystallites in the crystal lattice and this leads to an improvement in the monocrystallinity of silicon.

Surface-Modified Iron Oxide Nanoparticles with Natural Biopolymers for Magnetic Hyperthermia: Effect of Reducing Agents and Type of Biopolymers

Magnetic fluid hyperthermia, a minimally invasive localized therapy that uses heat generated by magnetic nanoparticles under an AC magnetic field, is a complementary approach for cancer treatment that is excellent due to its advantages of being noninvasive and addressing only the affected region. Still, its use as a stand-alone therapy is hindered by the simultaneous requirement of nanoparticle biocompatibility, good heating efficiency, and physiological safe dose. To overcome these limits, the biocompatible magnetic nanoparticles’ heating efficiency must be optimized. Iron oxide nanoparticles are accepted as the more biocompatible magnetic nanoparticles available. Therefore, in this work, superparamagnetic iron oxide nanoparticles were synthesized by a low-cost coprecipitation method and modified with starch and gum to increase their heating efficiency and compatibility with living tissues. Two different reducing agents, sodium hydroxide (NaOH) and ammonium hydroxide (NH4OH), were used to compare their influence. The X-ray diffraction results indicate the formation of a single magnetite/maghemite phase in all cases, with the particle size distribution depending on the coating and reducing agent. Citric acid functionalized water-based ferrofluids were also prepared to study the heating efficiency of the nanoparticles under a magnetic field with a 274 kHz frequency and a 14 kAm−1 amplitude. The samples prepared with NaOH display a higher specific loss power (SLP) compared to the ones prepared with NH4OH. The SLP value of 72 Wg−1 for the magnetic nanoparticles coated with a combination of starch and gum arabic, corresponding to an intrinsic loss power (ILP) of 2.60 nWg−1, indicates that they are potential materials for magnetic hyperthermia therapy.

Angle‐Resolved Polarized Raman Study of Layered Cr2Se3

ABSTRACTThe polarization‐resolved Raman spectra of two‐dimensional Cr2Se3 synthesized via chemical vapor deposition (CVD) and chemical vapor transport (CVT) techniques were investigated in detail. The samples were characterized using X‐ray diffraction (XRD), transmission electron microscopy (TEM), and energy‐dispersive X‐ray spectroscopy (EDS). A distinct polarization dependence was observed in the Raman intensity of all the Cr‐Cr, Cr‐Se, and Se‐Se modes in both samples. The observed angle‐dependent Raman intensities of each peak could be related to the crystal structure‐specific Raman tensor. XRD results of the bulk Cr2Se3 sample synthesized via CVT confirm its trigonal crystal structure, and the Raman peaks can be fitted using the Raman tensors for the 𝐴𝑔 and 𝐸𝑔 modes for both the parallel and crossed polarizations. However, for the Cr2Se3 samples directly grown on Si/SiO2 substrates by CVD, it was necessary to assume the triclinic crystal structure in order to explain the polarized Raman dependence of all the peaks in both parallel and crossed polarization directions. This is the first experimental result suggesting the existence of triclinic Cr2Se3 crystal structure, which has been theoretically predicted in the Materials Project database.

Development of Novel Biocomposites with Antimicrobial-Activity-Based Magnesium-Doped Hydroxyapatite with Amoxicillin.

Background/Objectives: A biocomposite based on magnesium-doped hydroxyapatite and enriched with amoxicillin (MgHApOx) was synthesized using the coprecipitation method and is presented here for the first time. Methods: The stability of MgHAp and MgHApOx suspensions was evaluated by ultrasound measurements. The structure of the synthesized MgHAp and MgHApOx was examined with X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The crystalline structure was determined by X-ray diffraction. The FTIR data were collected in the range of 4000-400 cm-1. The morphology of the nanoparticles was evaluated by scanning electron microscopy (SEM). Furthermore, the biocompatible properties of MgHAp, MgHApOx and amoxicillin (Ox) suspensions were assessed using human fetal osteoblastic cells (hFOB 1.19 cell line). The antimicrobial properties of the MgHAp, MgHApOx and Ox suspension nanoparticles were assessed using the standard reference microbial strains Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922 and Candida albicans ATCC 10231. Results: X-ray studies have shown that the biocomposite retains the characteristics of HAp and amoxicillin. The SEM assessment exhibited that the apatite contains particles at nanometric scale with acicular flakes morphology. The XRD and SEM results exhibited crystalline nanoparticles. The average crystallite size calculated from XRD analysis increased from 15.31 nm for MgHAp to 17.79 nm in the case of the MgHApOx sample. The energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) analysis highlighted the presence of the constituent elements of MgHAp and amoxicillin. Moreover, XPS confirmed the substitution of Ca2+ ions with Mg2+ and the presence of amoxicillin constituents in the MgHAp lattice. The results of the in vitro antimicrobial assay demonstrated that MgHAp, MgHApOx and Ox suspensions exhibited good antimicrobial activity against the tested microbial strains. The results showed that the antimicrobial activity of the samples was influenced by the presence of the antibiotic and also by the incubation time. Conclusions: The findings from the biological assays indicate that MgHAp and MgHApOx are promising candidates for the development of new biocompatible and antimicrobial agents for biomedical applications.

Hydrogen Bond Integration in Potato Microstructure: Effects of Water Removal, Thermal Treatment, and Cooking Techniques

Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Scanning electron microscopy (SEM) were used to study the effects of heat treatments and water removal by freeze-drying after different time intervals (6, 12, 24, 48, and 72 h) on the molecular structure of potato tubers. SEM images show structural differences between raw (RP), microwaved (MP), and boiled potato (BP). MP showed a cracked structure. BP was able to re-associate into a granule-like structure after 6 h of freeze-dying, whereas RP had dried granules within a porous matrix after 24 h of freeze-drying. These results are consistent with the moisture content and FTIR results for MP and BP, which demonstrated dried spectra after 6 h of freeze-drying and relatively coincided with RP results after 24 h of freeze-drying. Additionally, three types of hydrogen bonds have been characterized between water and starch, and the prevalence of water very weakly bound to starch has also been detected. The relative crystallinity (RC) was increased by thermal treatment, whereby microwaving recorded the highest value. A comparison of the FTIR and XRD results indicated that freeze-drying treatment overcomes heat effects to generate an integral starch molecule.

The effect of thermal annealing of GO/PVA on their physical, structural, and morphological properties

ABSTRACT In this research the synthesis of graphene oxide (GO) through the Hummers method, to obtain various percentage nanocomposite materials incorporating GO into polyvinyl alcohol (PVA) (2%GO/PVA, 3%GO/PVA, and 20%GO/PVA), and the detailed investigation of these composites’ morphological, structural, and optical characteristics using X-ray diffraction (XRD), Fourier-transform infrared (FTIR), Raman spectroscopy, and Scanning electron microscopy (SEM). The main goal of the presented work is to investigate how the physical properties change in the wide-range concentrations of the GO/PVA composite materials, as well as at different thermal annealing temperatures. From the XRD results, the space between the sheets is decreased by increasing the thermal annealing temperature. By the Halder-Wagner method, crystallite size and microstrain of the various percentages of GO/PVA were determined. The high microstrain and crystallite size belong to thermal annealed at 70°C of 3% GO/PVA (D = 8.50 nm/ε = 11%) and thermal annealed at 40°C of 20% GO/PVA (D = 13.70 nm/ε = 16 %). At room temperature and the highest annealing temperature, the microstrain value is minimal or equal to 0, because, its crystal structure is stable at low temperatures and it occurs as a result of relaxation due to rearrangement of the polymer chain at high temperatures. From Raman measurements, the ID/IG ratio for 2% and 3% GO/PVA composite materials increased with increasing temperature compared to the pristine GO. This indicates that the defect in the structure increases due to temperature.

Sintering polycrystalline silicon carbide composite ceramics with ultra-high hardness under high pressure

Silicon carbide (SiC) is an important structural ceramic material, exhibiting exceptional comprehensive properties that are unmatched by metals and other structural materials. In this study, a combination of α-SiC micron powder and β-SiC nanopowder was utilized as precursor materials for high pressure and high temperature (HPHT) sintering. Under a pressure of 5.0 GPa, polycrystalline SiC samples with mixed grain size were sintered within a temperature range from 1000 to 1700 °C, and compared with SiC samples sintered from single micron powder under identical temperature and pressure conditions. The microstructures of the two sets of SiC samples were observed using scanning electron microscopy. Additionally, the stress states and strengthening mechanisms among SiC grains with mixed grain size under HPHT were further analyzed in conjunction with X-ray diffraction results. The polycrystalline SiC composite ceramics sintered at 1700 °C exhibited superior mechanical and thermal properties, achieving a Vickers hardness of 35.2 GPa that is 23.5 % higher than that obtained by conventional spark plasma sintering and even surpassing the hardness of single crystal SiC, demonstrating thermal stability up to 1405 °C in air environment. Transmission electron microscopy was employed to analyze defects and plastic deformation in these samples. The study suggests that the primary strengthening mechanisms of the sintered polycrystalline SiC composite ceramics under HPHT include the increase in micro defects induced by in-situ plastic deformation at elevated temperatures and the effects of high-temperature creep. This study provides new insights into the HPHT sintering of hard materials.

Effects of Ultrasonic Vibration on 3D Printing of Polylactic Acid/Akermanite Nanocomposite Scaffolds

The mechanical properties of 3D-printed scaffolds for load-bearing implantation are crucial. Although the addition of nanoparticles to polymeric matrix scaffolds can improve their mechanical and biological properties, due to certain limitations in printability, high amounts of reinforcement cannot be used. Therefore, in this study, an attempt was made to use ultrasonic (UT) vibration to inhibit nozzle clogging during fused filament fabrication (FFF) of polylactic acid (PLA) scaffolds including 0, 20, and 40 wt.% Akermanite (Ak). Nozzle clogging happened during the conventional 3D printing of PLA-40wt.%Ak, while that did not occur during UT-assisted 3D printing of PLA-40wt.%Ak. Results of X-ray Diffraction (XRD) analysis and Scanning Electron Microscopy (SEM) indicated that applying ultrasonic (UT) vibration had no negative effect on the phases and morphology of the scaffolds. The results obtained by the compression test indicated that applying UT during 3D-printing resulted in almost 27% increment of elastic modulus and almost 25% increase of the compressive strength of the scaffolds. As the conclusion, this study highlights the effectiveness of ultrasonic-assisted 3D printing in producing nanocomposite scaffolds with significantly higher nanoparticle loadings, as compared to conventional printing methods. By utilizing ultrasonic vibration during the printing process, the study showcases the possibility of overcoming viscosity limitations and optimizing the mechanical performance of scaffolds for various biomedical applications, including bone tissue engineering.

Utilization of marine waste enteromorpha prolifera powder to prepare sustainable lightweight cementitious materials

This study innovatively used enteromorpha prolifera powder (EPP) to prepare lightweight cementitious materials. The effect of EPP on the physical properties, mechanical strengths, and microstructure of mortar was tested and discussed. The results indicated that the density and thermal conductivity of mortar were significantly reduced after adding EPP, but the water absorption and porosity were increased accordingly, resulting in a significant loss of mechanical strength. Surprisingly, the density and thermal conductivity of mortar incorporated with 8 % EPP was only 855.00 kg/m3 and 0.28 W/m•K (reduced by 57 % and 83 % respectively compared with plain mortar), and the 28 d compressive strength was still as high as 1.90 MPa. The results of thermogravimetric analysis and X-ray diffraction showed that as the EPP content increases, the Ca(OH)2 content decreases, and the CaCO3 content increases. This was due to the increase in porosity causing CO2 in the environment to enter the interior of the matrix. This study not only proposed new material for preparing sustainable lightweight cement mortar but also found a new way to utilize large amounts of waste enteromorpha prolifera resources.

Novel Ag-Doped- Poly (aniline-co-pyrrole)/Titanium-Dioxide Nanocomposite Sensor Material for Ammonia Detection in Spoiled Meat

Silver-doped poly(aniline-co-pyrrole)/titanium dioxide (Ag-doped PANI-PPy/TiO2) conducting copolymer-based nanocomposite ammonia gas sensor was synthesized through in situ chemical oxidative polymerization by taking different amounts (4%, 5%, 6%, 7%, and 8%) of Ag-TiO2 (1:1 ratio) nanoparticles. Zetasizer; dynamic light scattering, scanning electron microscopy, transmit ion electron microscopy, Fourier transform infrared, X-ray diffraction, UV–vis spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and cyclic voltammetry characterization techniques were used to confirm the real formation of nanocomposites and to evaluate the detection performance of the sensor. The interaction sensitivity of the synthesized nanocomposite sensor with ammonia (NH3) was determined by changing the amounts of nanoparticles. Spectroscopic determination exhibited excellent porosity and a better shift in the absorption bands having band gaps (1.87 eV) for the Ag-doped PANI-PPy/TiO2 nanocomposite sensor than the PANI-PPy copolymer (3.17 eV). Morphological (10 μm) and nanoparticle arrangement studies (20 μm) have shown the uniform allocation of nanoparticles in the copolymer matrix when 6% of Ag-TiO2 (1:1 ratio) was added, while agglomeration occurred when <6% or >6% of Ag-TiO2 was added to the copolymer. A decrease in the amorphous domain of the copolymer with an increase in nanoparticles was observed from the X-ray diffraction and other results.

Synergistic impact of lanthanum and cerium co-doping ZnO for improved photocatalytic rhodamine B degradation efficiency under UV light

In this study, the influence of different La and Ce co-doping amounts on the structural, morphological, optical, and photodegradation properties of ZnO nanostructures was evaluated. Zn1-2xLaxCexO nanoparticles (NPs) were prepared using sol-gel auto-ignition process, where x = 0.00 (pure ZnO), 0.01 (LC1), 0.03 (LC3), and 0.05 (LC5). The X-ray diffraction (XRD) and Raman results revealed that the prepared ZnO NPs crystallize in the hexagonal wurtzite structure. The size of crystallites is affected by the increment of La and Ce and it decreased from 24.29 nm to 10.40 nm with the increase in the concentration of La and Ce. Transmission electron microscopy (TEM) showed that the samples exhibit an irregular distribution of NPs with a dominant spherical shape morphology. The simultaneous incorporation of La and Ce in ZnO NPs led to a slight variation in the absorption edge and a slight shift in the values of the band gap energy from 3.20 to 3.24 eV. Furthermore, a reduction in the recombination rate of photogenerated charge carriers and the creation of fewer additional defects upon the appropriate insertion of Ce and La ions are highlighted by the analysis of photoluminescence spectra, Nyquist plots, and transient photocurrent measurements. The photocatalytic activity of samples was evaluated against rhodamine B organic dye under UV light irradiation. The analysis showed that LC1 sample exhibited superior photocatalytic performance with 99.1% degradation efficiency and a degradation rate constant of 0.0762 min-1. This enhancement has been ascribed to the surface defects and the optimized crystallite size achieved, which help to generate reactive entities such as •OH and O2•− in addition to the great role of holes (h+) and impede the recombination of charge carriers e-/h+.

The Role of Fabricated Coral Shell Powder in the Healing of Mandibular Bone Gap in Dogs

Background: The reconstruction of mandibular bone defects poses a real challenge and difficulty for surgeons; biomaterial bone substitutes are the most used material for reconstructing mandibular bone defects. Objectives: This study explored the role of fabricated hydroxyapatite (HAp) powder from the coral shell in healing critical size mandible gaps in dogs. Methods: HAp was prepared using the hydrothermal method from coral shells. Characterization of the fabricated coral shell was done by x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive x-ray spectroscopy (EDX). The designed research was performed on 18 dogs of both sexes (mean weight: 20±0.5 kg, mean age: 2±0.6 years). The samples were divided into two equal groups. Animals underwent experimental defects at the ventral surface of the lower mandible about 14.5 mm. Results: The results of XRD represented high crystallinity, the EDX results indicated the surface morphology of distributed particles of calcium, phosphorous, carbon, and oxygen, respectively, and the FESEM results suggested that the surface morphology of HAp appears as a spherical particle that regularly distributed within the sample. In the HAp group, at 30 days, the FESEM images show that the defective gap completely closed, and the center of the defect was filled with a thick layer of osteoid matrix. Radiographically, the HAp group at 30 days post-surgery indicated a well-defined circular radiolucent bone gap at the caudal portion of the mandible, with a partially sclerosed margin. Macroscopically, at 30 days, the gap appears very small and is invaded by new bone formation. Conclusion: In conclusion, recycling HAp from coral shells has practical value in the reconstitution of the mandibular gap, and the radiological and critical properties of prepared HAp emphasize this outcome.

Microwave absorption studies in X-band of magnetized barium hexaferrite

Abstract To enhance the magnetic and microwave absorbing properties, barium hexaferrite, BaFe12O19, was studied in the x-band (7–13 GHz) frequency range. The BaFe12O19 was prepared as non-magnetized and magnetized samples. The crystal structure, surface morphology, magnetic and microwave absorption of BaFe12O19 were studied with X-ray diffraction (XRD), optical microscope, permagraph and vector network analyzer (VNA), respectively. XRD result showed the formation of M-type hexagonal polycrystalline structure. The hysteresis loop results verified the formation of permanent magnet with high saturation magnetization. The VNA results showed that reflection loss and absorption were − 71.07 dB and 67.96% for magnetized barium hexaferrite, respectively.

Green chemistry approach for the synthesis of CrxCu1-xO nanoparticles: An investigation of the structural and dielectric properties

Chromium (Cr)-doped copper oxide (CrxCu1-xO, x = 0, 0.02, 0.04, 0.06, 0.10) nanoparticles were prepared by a green chemistry approach using Juglans regia fruit extract. The characteristics of pristine and Cr-doped CuO were examined in relation to the concentration of the dopant (2, 4, 6, and 10mol%) using X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) Scanning electron microscopy (SEM), Energy dispersive analysis (EDX), and UV-Vis. spectroscopy (UV-Vis). According to the XRD results, the synthesized samples exhibited a polycrystalline nature and monoclinic crystal structure. It was discovered that the average grain size varies from 22.4nm to 17.82nm because of the addition of dopants. The optical analysis revealed an increase in the band gap from 1.62 to 3.10eV. We performed the dielectric analysis of pure and Cr-doped CuO nanoparticles and analyzed the behavior of dielectric parameters like dielectric constant, dielectric loss, and ac conductivity with frequency. The dielectric constant and loss exhibit a decreasing trend with frequency whereas ac conductivity demonstrates an increasing trend with frequency and composition.

Characterization of Mn3O4/(x)Nb2O5 thin films as a promising material for supercapacitors

The thin films of Mn3O4/(x)Nb2O5 oxides (x = 0, 2, 4, and 6 %) were prepared by the electron beam evaporation method and then annealed at 400 °C. The structural analysis showed a tetragonal phase of Mn3O4, according to X-ray diffraction results. The quantitative elemental analysis of films confirms the stoichiometry of the Mn3O4, while the Nb2O5 couldn’t be recognized using energy dispersive X-ray fluorescence. The chemical speciation of the films was investigated using X-ray photoelectron spectroscopy. Three oxidation states of Mn were recognized at average binding energies of 645.70±0.35, 642.99±0.40, and 641.58±0.48 eV that correlated to Mn4+, Mn3+, and Mn2+, respectively. As the Nb2O5 increases, a slight decrease in the binding energy of Mn4+ is recognized, whereas it is nearly constant for the deconvoluted Mn3+ and Mn2+. Two electronic transitions (Eg1 and Eg2) of the optical band gap showed an increase with increasing Nb2O5 dopant from 2 % to 6 %. The optical parameters such as Eosc, the single oscillator energy, Edis, the dispersion energy, both moments (M−1) and (M−3), the ratio of carrier concentration/effective mass (N/m*), and the lattice dielectric constant (εL) were determined. From electrochemical measurements of pure Mn3O4 films, it is found that the voltammetric current density is directly proportional to the scan rates of cyclic voltammetry CV, with good cyclic stability, and by increasing the scan rates, the values of specific capacitance decrease while the values of specific power increase. In doped thin films, no potential drop is observed in the discharging process, which indicates good interfacial contact between the active material and the substrate during the charge/discharge process. These results suggest that the obtained Mn3O4 nanoparticles are a better candidate for supercapacitor applications.

Controlled growth of ruthenium dioxide nanostructures in borosilicate glass melts

Ruthenium, a fission product generated during the fission of uranium oxide fuel in a reactor, interacts with alkali metals such as sodium in the upper layer of the cold cap, forming a sodium ruthenate intermediate (NaxRuyOz), which promotes the crystallization of acicular RuO2 within the glass melt. During vitrification, RuO2 predominantly settles at the bottom of the melt owing to its high density and low solubility, significantly increasing both the conductivity and viscosity of the glass melt. Herein, the formation of NaxRuyOz, along with the chemical reactions promoting the crystallization of RuO2 in the waste glass, was comprehensively investigated. The results of X-ray diffraction and X-ray spectroscopy indicate that lamellar and granular Na3RuO4 do not form directly through the reaction between NaNO3 and RuO2 but rather through an intermediate stage from Na2RuO4. This reaction critically affects the morphology of RuO2 within the waste glass. The uncalcined mixture of NaNO3 and RuO2 was found to interact with the glass melt, forming granular RuO2 crystals, whereas the reaction of Na3RuO4 with the glass melt was found to lead to the formation of acicular RuO2 crystals. The results of X-ray absorption fine structure analysis indicate that the valence state of Ru in NaRu-BSG is slightly higher than that in reference RuO2, which was attributed to the presence of trace amounts of Na3RuO4 in the glass.

(10–13)-oriented semipolar GaN growth on (10–10) m-plane ScAlMgO4 substrate

Abstract We report the growth of a GaN layer on (10–10) m-plane ScAlMgO4 (SAM) substrate. The GaN layer demonstrated (10–13) preference growth orientation. The anisotropy of the crystalline quality was distinctly observed through X-ray rocking curve taken across the sample surface over various azimuths across the orthogonal directions [0001] and [1–210] of the SAM substrate. Notably, the crystalline quality exhibited gradual degradation as the substrate is rotated around its surface normal away from the c-direction [0001] of the SAM substrate toward the a-direction [11–20]. Additionally, basal stacking faults in the (10–13)-oriented GaN were observed along [0001] direction using scanning transmission electron microscopy. Moreover, the selected area electron diffraction analysis was utilized to confirm the (10–13) growth orientation that was found to be consistent with the X-ray diffraction result. The (10–13) GaN layer exhibited a metal face through integrated differential phase contrast imaging.