Different Concentrations Of Mg Research Articles

Thermoluminescence and kinetic parameters of irradiated dopant calcium aluminate nanophosphors

CaAl2O4:0.1% La nanoparticles doped with different concentrations of Mg were prepared using the sol–gel method and annealed at 400 °C, 500 °C, and 800 °C, respectively. The prepared nanophosphors show a highly crystalline orthorhombic structure with a crystallite size of about 81.2 nm. The optimum concentration of Mg dopants is about 0.7 mol%. The thermoluminescence (TL) glow curve of 11 Gy of beta-ray irradiated CaAl2O4:0.1% La:0.7% Mg measured at heating rates of 5 K/s has 16 overlapping glow peaks. The TL kinetic parameters for the prepared nanoparticles were evaluated using two different methods and they exhibited good agreement. Moreover, the linearity dose response of dosimetric peaks follows a good linearity up to 220 Gy in nanophosphor. The minimum detectable dose of the prepared nanophosphor was 125.7 mGy. The results of the prepared nanophosphors suggest good candidates for dosimetric applications.Graphical abstract

Phenotypic Variations in Banana Cultivars in the Utilization and Tolerance to Different Magnesium Levels

Magnesium (Mg) is the most commonly deficient nutrient in tropical banana-growing areas. The effects of different concentrations of Mg on morpho-physiological and biochemical responses on three commercial cultivars (Baxi, Haigong, and Guangfen No.1) of bananas were accessed for 12 weeks. Results showed genotypic variation in the utilization and tolerance to different Mg levels. The optimum Mg level was 1 mM for Baxi and Guangfen No.1 and 3 mM for Haigong. Both the deficiency and excess of Mg caused a severe reduction in plant height, dry weight, total root length, and root surface area of Haigong and Baxi. Mg stress reduced root growth by impairing photosynthate translocation and increased carbohydrate contents in the source leaf. Under Mg stress, more reduction in photosynthetic pigment and photosynthesis rate, higher accumulation of carbohydrates and malondialdehyde contents, and higher activities of antioxidative enzymes were observed in Haigong as compared to other genotypes. Based on the above results, it is concluded that Haigong is most sensitive to Mg stress while Guangfen No. 1 was least affected and tolerant to changes in the Mg levels.

Study on the effect of magnesium on leaf metabolites, growth and quality of tea tree.

Magnesium (Mg) is one of the essential elements for the growth of tea trees. In this study, we investigated changes in metabolites, photosynthetic fluorescence parameters and quality indexes of tea leaves under different concentrations of magnesium treatment, and the results showed that there were no significant differences in the quantity and total content of metabolites in tea leaves under different Mg concentrations. The results of volcano map analysis showed that the content of 235 metabolites in tea leaves showed an increasing trend and the content of 243 metabolites showed a decreasing trend with the increase of Mg concentration. The results of the combined analysis of the OPLS-DA model and bubble map showed that 45 characteristic metabolites were screened at different concentrations of Mg. Among these, the content of 24 characteristic metabolites showed an increasing trend and 21 characteristic metabolites showed a decreasing trend with the increase of Mg concentrations. The results of KEEG pathway enrichment showed that 24 characteristic metabolites with a upward trend were significantly enriched in saccharides metabolism, nucleic acid metabolism and vitamin metabolism, while the 21 characteristic metabolites with a downward trend were enriched in the synthesis of plant secondary metabolites, phenylpropanoid biosynthesis, biosynthesis of terpenoids, synthesis and metabolism of alkaloids, and synthesis and metabolism of amino acids. It can be inferred that Mg regulation was beneficial to enhance the photosynthetic capacity of tea trees, improve the accumulation and metabolism of carbohydrate substances in tea trees, and thus promoted the growth of tea trees, but was not conducive to the synthesis of secondary metabolites and amino acids related to tea quality. The results of photosynthetic fluorescence parameters and quality indexes of the tea tree confirmed the conclusion predicted by metabolomics. This study provided a reference for regulating of the growth and quality of tea trees with Mg fertilizer in tea plantations.

Study on Effect and Mechanism of Alkaline Earth Metal Poisoning on Cu/SSZ-13 Catalysts for Selective Catalytic Reduction of NOx with NH3

In order to study the poisoning effect of the alkaline earth metal on Cu/SSZ-13 and reveal the poisoning mechanism, Cu/SSZ-13 zeolite catalysts were synthesized by the ion-exchange method and poisoned by different concentrations of Mg and Ca. The results of SCR tests and characterizations showed that the SCR activity of Cu/SSZ-13 catalysts decreased obviously after Mg or Ca poisoning, which is because Mg and Ca reduced the Cu2+ species and Brønsted acid sites in Cu/SSZ-13, while increasing the content of CuxOy. Furthermore, Mg and Ca on the catalyst surface could block the pores of the zeolite and then decrease the specific surface area of the catalysts, and Ca could further cause partial collapse of the zeolite skeleton. Through this article, the effect and mechanism of alkali earth metal poisoning of Cu/SSZ-13 were revealed, which provided data and theory support for the development of efficient Cu/SSZ-13 NH3-SCR catalysts with high alkali earth metal resistance.

Gene-nutrient interactions that impact magnesium homeostasis increase risk for neural tube defects in mice exposed to dolutegravir.

In 2018, data from a surveillance study in Botswana evaluating adverse birth outcomes raised concerns that women on antiretroviral therapy (ART) containing dolutegravir (DTG) may be at increased risk for neural tube defects (NTDs). The mechanism of action for DTG involves chelation of Mg2+ ions in the active site of the viral integrase. Plasma Mg2+ homeostasis is maintained primarily through dietary intake and reabsorption in the kidneys. Inadequate dietary Mg2+ intake over several months results in slow depletion of plasma Mg2+ and chronic latent hypomagnesemia, a condition prevalent in women of reproductive age worldwide. Mg2+ is critical for normal embryonic development and neural tube closure. We hypothesized that DTG therapy might slowly deplete plasma Mg2+ and reduce the amount available to the embryo, and that mice with pre-existing hypomagnesemia due to genetic variation and/or dietary Mg2+ insufficiency at the time of conception and initiation of DTG treatment would be at increased risk for NTDs. We used two different approaches to test our hypothesis: 1) we selected mouse strains that had inherently different basal plasma Mg2+ levels and 2) placed mice on diets with different concentrations of Mg2+. Plasma and urine Mg2+ were determined prior to timed mating. Pregnant mice were treated daily with vehicle or DTG beginning on the day of conception and embryos examined for NTDs on gestational day 9.5. Plasma DTG was measured for pharmacokinetic analysis. Our results demonstrate that hypomagnesemia prior to conception, due to genetic variation and/or insufficient dietary Mg2+ intake, increases the risk for NTDs in mice exposed to DTG. We also analyzed whole-exome sequencing data from inbred mouse strains and identified 9 predicted deleterious missense variants in Fam111a that were unique to the LM/Bc strain. Human FAM111A variants are associated with hypomagnesemia and renal Mg2+ wasting. The LM/Bc strain exhibits this same phenotype and was the strain most susceptible to DTG-NTDs. Our results suggest that monitoring plasma Mg2+ levels in patients on ART regimens that include DTG, identifying other risk factors that impact Mg2+ homeostasis, and correcting deficiencies in this micronutrient might provide an effective strategy for mitigating NTD risk.

Substitutional effect of Mg2+ on structural and magnetic properties of La2MgxNi1‐xMnO6 double‐perovskite thin films

AbstractBy doping different concentrations of Mg2+ at Ni site, the (00l)‐oriented La2MgxNi1‐xMnO6 (abbreviated as LMxNMO, x = 0, 0.1, 0.2, 0.3, 0.4) double‐perovskite thin films were epitaxially grown by pulsed laser deposition. The substitutional effect of Mg2+ on the structural and magnetic properties of the films is comprehensively investigated. It is found that with the increase of Mg‐doping concentration, the in‐plane and out‐of‐plane lattice constants as well as the cell volume of the LMxNMO thin films increase, which could be ascribed to the radius difference between Mg2+ and Ni2+/Ni3+ ions, resulting in the in‐plane compressive stress in LMxNMO films. When the Mg‐doping concentration is small (x ≤ 0.1), the doped Mg2+ tends to substitute Ni3+, which restrains the intensity of antiferromagnetic interaction between Ni3+‐O‐Mn3+, resulting in the reduced the exchange bias field as well as the increased the saturation magnetization. However, when the Mg‐doping concentration increases to x ≥ 0.2, Mg2+ becomes to mainly replace Ni2+ position, which could inhibit the super‐exchange ferromagnetic interaction between Ni2+‐O‐Mn4+ magnetic paths and thus reduce the saturation magnetization. The enhanced magnetic properties can be obtained in the LM0.1NMO double‐perovskite thin film, with a large saturation magnetization of 492.12 emu/cm3 and a high Curie temperature of 262.7 K.

ХЕЛАТУВАННЯ ДВОВАЛЕНТНИХ КАТІОНІВ ТА АНТИРАКОВА АКТИВНІСТЬПОХІДНИХ 8-ГІДРОКСИСТИРИЛХІНОЛІНІВ IN VITRO

Background. The search for new methods of cancer treatment and diagnosis are important. The disadvantages of chemotherapy drugs are the rapid acquisition of resistance and high toxicity. 8-hydroxyquinoline derivatives have a wide spectrum of biological activity and have the necessary properties for fluorescent cancer diagnosis. The aim of the study was to determine the chelation of calcium, magnesium and zinc cations by hydrophobic derivatives of 8-hydroxystyrylquinolines (8HQ) 2-(4-chlorostyryl)quinolin-8-ol (STQ-Cl) and 2-(4-nitrostyryl)quinolin-8-ol (STQ-NO2) in physiological solution, the stability of the complexes and the cytotoxicity of the compounds to prostate and breast cancer cell lines in vitro. Methods. 8HQ derivatives STQ-Cl and STQ-NO2 were used. Solutions of Ca2+, Mg2+, Zn2+ cations were prepared by the method of two-fold dilutions in 0.5-0.0078125 mM concentration range based on 0.9 % NaCl. Both individual solutions of each cation and a mixture in an equivalent molar ratio were used. The concentration of 8HQ derivatives were 0.05 mM. Optical absorption was registered in 200-700 nm wavelength range. Cytotoxicity was investigated on breast (MDA-MB-231) and prostate (DU-145) cancer cell lines. STQ-Cl and STQ-NO2 derivatives in DMSO were added to the incubation solution by four-fold dilutions (0.125–0.00003 mM). For luminescence studies, MDA-MB-231 and DU-145 cells were grown on coverslips. The final concentration of 8HQ derivatives were 5 mM. Cells were kept for 5, 10, 20 and 30 min. Luminescence was recorded under the same conditions for all samples, with an exposure time of 10 ms. Results. Mg2+ and Ca2+ (0.03125 mM) were contributed to reduce the intensity of optical absorption maxima of STQ-Cl by 1.6 and 1.3 times, respectively. The effect was most pronounced at 0.015625 mM Zn2+. Weak differences in the optical absorption of solutions were detected when STQ-NO2 was incubated with different concentrations of Mg2+ and Ca2+. The optical absorption intensity of the STQ-NO2 aqueous solution was increased at 0.015625 and 0.03125 mM Zn2+. The maximum cytotoxicity against MDA-MB-231 cells for STQ-Cl was about 80 %, and STQ-NO2 was 60 % at 0.04 mM Zn2+. DU-145 cells were more sensitive to STQ-NO2 (EC50 = 0.011 mM), but weakly sensitive to STQ-Cl (50 % at 0.125 mM). The maximum luminescence intensity was after 20 min of incubation with STQ-Cl and STQ-NO2 (5 mM) for both cells lines and was not change over time. Conclusions. The decrease of optical absorption maxima of STQ-Cl aqueous solutions in the presence of magnesium, calcium, and zinc cations was a consequence of aggregation processes. This phenomenon was probably the reason for the different cytotoxicity of STQ-Cl and STQ-NO2, as well as the presence of other mechanisms of action to cancer cells. Results was a consequence of different affinity of 8-hydroxyquinoline derivatives to magnesium, calcium and zinc cations, solubility in water, stability, aggregation of metal complexes and free compounds.

Influence of Magnesium Content on the Physico-Chemical Properties of Hydroxyapatite Electrochemically Deposited on a Nanostructured Titanium Surface

The aim of this research was to obtain hydroxyapatite (HAp)-based coatings doped with different concentrations of Mg on a Ti nanostructured surface through electrochemical techniques and to evaluate the influence of Mg content on the properties of HAp. The undoped and doped HAp-based coatings were electrochemically deposited in galvanostatic pulsed mode on titania nanotubes with a diameter of ~72 nm, being designed to enhance the adhesion of the HAp coatings to the Ti substrate. The obtained materials were investigated by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-Ray Diffraction (XRD), and Fourier-Transform Infra-Red spectroscopy (FTIR). The adhesion of the coatings to the substrate was also evaluated with the help of the “tape-test” and the micro-scratch test. The morphology (SEM) of all the coatings is made of very thin and narrow ribbon-like crystals, with some alterations with respect to the Mg amount in the coatings. Thus, a concentration of 1 mM of Mg in the electrolyte leads to wider and thicker ribbon-like crystals, while a concentration of 1.5 mM in the electrolyte generated a morphology that resembles the undoped HAp. Both phase composition (XRD) and chemical bonds (FTIR) analysis proved the formation of HAp in all coatings. Moreover, according to XRD, all coatings have a strong orientation toward the (002) plane. Irrespective of the Mg content, all coatings registered an average roughness between approx. 500 and 600 nm, while the coating thickness increased after addition of Mg, from a value of 9.6 μm, for the undoped HAp, to 11.3 μm and ~13.7 μm for H/Mg1 and H/Mg2, respectively. In terms of adhesion, it was shown that the coatings a H/Mg2 had a poorer adhesion when compared to H/Mg1 and the undoped HAp (H), which registered similar adhesion, indicating that a concentration of 1.5 mM of Mg in the electrolyte reduces the adhesion of the Hap-based coatings to the nanostructured surface. The obtained results indicated that Mg concentrations up to 1 mM in the electrolyte can enhance the properties of HAp-based coatings electrochemically deposited on a nanostructured surface, while even a slightly higher concentration of 1.5 mM can negatively impact the characteristics of HAp coatings.

Effect of Mg2+/Sr2+ addition on luminescence properties of Dy3+ doped glass ceramics containing Ca2Ti2O6

Dy2O3-doped transparent glass-ceramics containing Ca2Ti2O6 crystal phase were synthesized by melting crystallization method. The optimum heat treatment condition was determined to be 710 °C/1.5 h by differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmittance curves. The optimal doped concentration of Dy2O3 is 0.4 mol%. The effects of doping with different concentrations of Mg2+ and Sr2+ on the fluorescence intensity of glass-ceramics were discussed. In comparison to Sr2+, the addition of Mg2+ effectively increased the luminescence intensity of 0.4 mol% Dy2O3-doped glass-ceramics. Since Mg2+ has a smaller ionic radius, it has a larger Coulomb potential and is more attractive to O2−, which makes the three-dimensional skeleton of BO6 tilt, and the symmetry of the structure deteriorates, resulting in enhanced luminescence. Comparison of 0.4 mol%Dy2O3-doped glass-ceramic and 8 mol%MgF2-0.4 mol%Dy2O3 co-doped glass-ceramic, the fluorescence intensity increased by 56.8% at 484 nm and 83.5% at 577 nm, the optical band gap value was reduced from 2.7824 eV to 2.4341 eV. The findings suggest that Dy3+-doped glass-ceramics containing Ca2Ti2O6 crystal phase will be used in white light-emitting diodes (W-LEDs).

Osteoimmunomodulatory properties of a magnesium-doped phase-transited lysozyme coating on titanium

The inflammation aroused by implants is the main cause of implant failure. Therefore, the design paradigm of implants has changed from “inertia” to “immunomodulatory”. Although multiple bioactive ions exert effects on osteogenesis, how magnesium ions (Mg2+) manipulate immune response via inducing macrophage polarization and subsequently promote osteogenesis needs further investigation. In this study, phase-transited lysozyme (PTL) is deposited onto the surface of titanium (Ti) to construct a functional coating and magnesium chloride solution at 2.5 mM, 5 mM and 10 mM was utilized to produce PTL coatings with different concentrations of Mg2+ (PTL-Mg2.5, PTL-Mg5 and PTL-Mg10). The characterization of the magnesium-doped PTL coatings (PTL-Mg) was tested by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and inductively coupled plasma atomic emission spectroscopy (ICP-AES). In addition, we utilized a co-culture system of macrophages and rat bone merrow mesenchymal stem cells (BMSCs) to investigate the osteoimmunomodulatory effects of PTL-Mg coatings. The results showed that compared with other groups, PTL-Mg5 group can create a favorable osteoimmune microenvironment by regulating macrophages polarization and release of inflammatory cytokines, then promote adhesion, proliferation and osteogenic differentiation of BMSCs. The in vivo results further verified the most excellent osteointegration ability of PTL-Mg5 in rat femur lateral condyle defects. This work indicates a promising way for design paradigm of implants with immunomodulatory properties by inducing PTL-Mg5 coating on Ti, providing a new strategy for implants surface modification.

Ferroelectricity in hafnium oxide films doped with magnesium by chemical solution deposition

In this study, a series of ∼26 nm thick hafnium oxide films doped with different concentrations of Mg were prepared by the chemical solution deposition method. With the increase of Mg concentration, the film undergoes a phase transition from monoclinic, through orthorhombic, and then to cubic. Metal–insulator–semiconductor capacitors were fabricated, and the ferroelectricity was verified for films doped with an Mg concentration of 0.4–3.7 mol. %. For the film doped with 2.3 mol. % Mg, the remanent polarization is 16.4 μC/cm2 after the wake-up process, and 76.1% of the initial 2Pr value can be maintained after 107 cycles of bipolar field cycling. All the results show that Mg is a promising dopant to stabilize the ferroelectricity of hafnium oxide films.

Influence of Mg doping on the structural, electrical and dielectric properties of Co-Zn nanoferrites

Mg-Co-Zn nanoferrites of composition MgxCo0.5Zn0.5Fe2−xO4 (x = 0.25, 0.5, 0.75 and 1.0) were successfully synthesized by using a citrate precursor method. After synthesis, the samples were examined using different techniques for structural, morphological, electrical and dielectric characterizations. All the samples were found to have single phase spinel cubic structure with Fd-3m space group in the X-ray diffraction spectroscopy (XRD) investigation. The value of average crystallite size ranged from 37 to 47 nm with the increase in Mg ion concentration from x = 0.25 to 1.0. The hopping lengths at tetrahedral and octahedral sites showed an increasing behaviour with increasing magnesium ion concentration. The presence of tensile strain in the samples was confirmed by W-H plots. The dielectric behaviour of the prepared nanoferrites was recorded at room temperature in the frequency range 10 kHz–10 MHz. The real part and imaginary part of the dielectric constant were found to be in the range 3.80–7.93 and 0.0036–0.644 at 1 MHz frequency and the value of loss tangent was 0.00095–0.081 at 1 MHz for the magnesium doped Co-Zn nanoferrites. The value of loss tangent decreased very sharply to remarkably low values at 10 MHz frequency. The dc resistivity value was found very low in the range 3.2 × 108 Ω-cm to 4.0 × 109 Ω-cm for different concentrations of Mg2+ ions in the samples. Due to such low losses at high frequency region and high value of dc resistivity, these materials can be considered as potential candidate for high frequency applications.

Formation pathway of norsethite dominated by solution chemistry under ambient conditions

Abstract Recently dolomite analogs, including norsethite, kutnahorite, and PbMg(CO3)2, etc., have attracted much attention due to their dolomite-like crystallographic structure and the resulting potential in solving “dolomite problem.” Previous studies indicate that mechanisms that underlie the formation of norsethite exhibit some similarities to pathways of dolomite crystallization. However, the crystallization behavior of norsethite is still poorly understood, and the physicochemical factors regulating the process are not yet fully established. Herein, to determine the relationships between solution chemistry and formation pathway of norsethite, a series of experiments for the synthesis of norsethite from the solutions with different concentrations of Mg2+ and Ba2+ by a CO2 gas-diffusion method was carried out under ambient conditions. The morphology and phase composition of the products were investigated by a range of techniques, including XRD, FESEM, micro-Raman, and FTIR techniques. ICP-AES was used to monitor the evolution of the concentrations of Mg2+ and Ba2+ in the mineralization solutions. Our observations suggest that the formation pathway of norsethite strongly depends on Mg/Ba ratio in solution, and pure norsethite can directly crystallize from the solutions with Mg/Ba ratio ranging in 20–40. This is the first time to report the direct precipitation of dolomite analogs at ambient temperatures. It suggests that direct precipitation is a feasible pathway for cation ordering structure formation under ambient conditions.

The effect of electronegativity on optical properties of Mg doped ZnO

In this work, ZnO thin films are deposited on glass substrates by sol gel spin coating technique and doped at different concentration of Mg (1%, 2%, 3%, 4%, and 5% Mg). The structural, morphological and optical properties of ZnO doped Mg are investigated for improved thin film solar cell performance. The DRX result exhibit that once the Mg atoms was introduced in the ZnO structure, the peaks take a preferential orientation according to the (002) plane, reaching a maximum value at 2% Mg. This behavior has been attributed simultaneously to the difference of electronegativity between Zn and Mg, and variation of grain size.The variation of electronegativity affected also the optical properties where the transmittance reaches its maximum value of 90%at 3% Mg concentration. The gap energy reaches the maximum value in a sample with the highest crystallite size and the highest preferential orientation, which corresponds, to ZnO: 2% Mg.

Effect of Mg doping on the improvement of photoluminescence and magnetic properties of NiO nanoparticles

NiO nanoparticles doped with different concentration of Mg were synthesized by a low cost wet chemical method. XRD characterization indicated that the fcc structure of NiO is not affected with Mg doping. TEM analysis further reveals the Mg doping induced reduction in grain agglomeration along with the spherical shape transformation in NiO. Significant enhancement of UV emission in Mg doped NiO nanoparticles is evident from photoluminescence characterization. Magnetic characterization of the samples showed that all the samples show weak ferromagnetism along with the dominance of background antiferromagnetism at room temperature. The perseverance of background antiferromagnetic order is further probed through Raman characterization. All the samples show first order antiferromagnetic to weak ferromagnetic transition along with the presence of shape memory effect as evident by the negative slope in Arrott plot. The Ni0.9Mg0.1O sample with much enhanced UV emission and magnetization could find the usefulness in UV optoelectronic device, spintronic device etc.

Magnesium ion-conducting solid polymer electrolyte based on cellulose acetate with magnesium nitrate (Mg(NO3)2·6H2O) for electrochemical studies

In this paper, the solution casting technique was used to develop the magnesium-conducting solid polymer electrolyte (PE) using cellulose acetate (CA) with the magnesium nitrate (Mg(NO3)2·6H2O) salt. The crystalline/amorphous nature of CA with different concentrations of Mg(NO3)2·6H2O polymer electrolytes was studied by X-ray diffraction (XRD) analysis. The highest ionic conductivity of 9.19 × 10−4 S/cm was found for 60 wt.%CA/40 wt.% Mg(NO3)2·6H2O PE by Ac impedance spectroscopy at room temperature. The polymer membranes are subjected to FTIR analysis. The glass transition temperatures (Tg) of the PEs were determined using differential scanning calorimeter (DSC). Then, the transference number of Mg2+ ion for 60 wt.%CA/40 wt.% Mg(NO3)2·6H2O PE was measured as 0.35 using Evan’s method. The electrochemical stability of 3.65 V was observed for the highest ionic conducting PE by linear sweep voltammetry. The cyclic voltammetry (CV) study was done for highest ionic conducting polymer electrolyte. Finally, the primary magnesium battery was constructed with the highest ionic conducting PE, and its performance was studied.

A first-principles study of Mg/Ni induced magnetic properties of Zn0.95−xMgxNi0.05O

Magnetic properties of Mg/Ni doped ZnO were investigated by the first-principles study. The generalized gradient approximation (GGA) in Perdew–Burke–Ernzerhov of the scheme as a form of density functional theory (DFT) utilizing the plane-wave pseudo-potential method was used. Calculations were performed for a constant Ni doping ratio as 5% and different concentrations of Mg varying from 1% to 5%. It was shown that Mg concentrations helped to tune band gap and mediate the ferromagnetic property. 1% Mg-doped structure had a half-metallic ferromagnetic (HMF) state. Meanwhile, metallic behavior (MB) was observed for higher concentrations of Mg (>1%) impurities. It was revealed that Mg-doped ZnNiO possesses ferromagnetic behavior solely for 1% Mg while other doping ratios were showing distinctive phases including antiferromagnetism (AFM). Besides, there is no evidence of a clear connection between the doping concentration of the Mg and the magnetic phase. Ni distant/near oxygen vacancies (Vo) enhanced the FM state; however, distant vacancies led to HMF state for all Mg concentrations. Zn-d, O-p, and Ni-d (dominates) control the spin-up/down channels by hybridization.

Aqueous Foams in the Presence of Surfactant Crystals.

Aqueous foams are used extensively in many fields and anionic surfactants are commonly used foaming agents. However, potential trouble may arise when they are utilized in hard water areas and/or at low temperatures. Anionic surfactants, like sodium dodecyl sulfate (SDS), may precipitate in the form of crystals when the concentration of divalent counterions such as Mg2+ exceeds a certain limit. In an attempt to prepare ultrastable foams containing precipitated crystals, the behavior of SDS in water was systematically investigated as a function of surfactant concentration at different concentrations of Mg(NO3)2 prior to a study of their foam properties. We quantitatively study the conversion of surfactant micelles to crystals and the redissolution of crystals into micelles. It was found that the presence of surfactant crystals reduced the initial foam volume and foam half-life but greatly improved the long-term stability of foams. Foam studies were also conducted for the supernatant and sediment isolated from crystal dispersions so that the importance of surfactant crystals to foam stability could be established. Despite the foamability of a sediment being low, an order of magnitude increase in foam half-life was related to the coverage of bubble surfaces by surfactant crystals. Both rapid cooling and ultrasonication were shown to influence the surfactant crystal shape and size with an impact on foam properties.

Synthesis and characterization of Mg-doped ZnO thin-films electrochemically grown on FTO substrates for optoelectronic applications.

Mg-doped ZnO (MZO) thin films were successfully fabricated on fluorine-doped tin-oxide (FTO)-coated glass substrates by an electrochemical deposition method using aqueous electrolytes of 80 mM Zn(NO3)2 with different concentrations of Mg(NO3)2. The effects of Mg doping concentration on the electronic, microstructural, morphological, optical and electrical properties of the prepared films were investigated. The results of the Mott–Schottky (M–S) analysis revealed that the charge carrier density of n-type MZO films increases considerably when increasing the amount of Mg. As Mg concentration increased the Fermi level energy was also found to be increased by inclusion of Mg doping, which was confirmed by negative shifting of the flat band potential. XRD analysis showed that both undoped and Mg-doped ZnO thin films have a polycrystalline nature and hexagonal wurtzite structure with preferential orientation along the (002) axis. It is evident that the intensity of the (002) peak decreased with increasing Mg concentration. From scanning electron microscopy (SEM) analysis, it was found that when the amount of Mg concentration was increased in the solution, a decrease in the size of the grains was observed. The optical transmittance was found to be very high (∼85%) in the visible region of the solar spectrum. When the Mg content in the ZnO system was increased, a blue shifting of the absorption edge of the films was observed. The result of I–V measurements showed that the Mg doping was found to lead to an enhancement of the electrical properties of MZO thin films and the design of high-performance transparent conductive oxide (TCO) material.

Crystal structure and electronic properties of wurtzite MgxZn1-xO: Ab initio study

The current paper reports on the alloying effect on the structural and electronic properties of the hexagonal wurtzite MgxZn1-xO. The calculations are carried out using full-potential linearized augmented plane wave method. The Wu-Cohen and Tran-Blaha modified Becke-Johnson generalized gradient approximations are used to describe the exchange-correlation potential. Our results show generally reasonable accord with experiment. By alloying ZnO with different concentrations of Mg, the variation of the lattice parameters versus Mg content violates slightly the Vegard's law. The analyses of the band structure and density of states show that MgxZn1-xO (0 ≤ x ≤ 1) exhibits a semiconducting character with a direct band-gap (Г-Г). The variation of the latter versus alloy composition x is found to be non-linear showing a band-gap bowing parameter of −1.33 eV.