Microspheres of Ni_(0.5)Co_(0.5)Ga_(x)Fe_(2-x)O_(4)(x≤1.0)microsphere spinel ferrites(NiCoGaFe-MSFs)and carbon spheres were prepared via a hydrothermal technique.The micro structure of microspheres was investigated t...Microspheres of Ni_(0.5)Co_(0.5)Ga_(x)Fe_(2-x)O_(4)(x≤1.0)microsphere spinel ferrites(NiCoGaFe-MSFs)and carbon spheres were prepared via a hydrothermal technique.The micro structure of microspheres was investigated through scanning and transmission electron microscopy(SEM and TEM),respectively,and X-ray diffraction(XRD).The electrical and dielectric properties of NiCoGaFe-MSF at temperatures ranging from20 to 120℃(between 293,1×10^(3)and 393.1×10^(3))for f≤3.0 MHz were systematically studied as a result of 3D graphical drawing of the data obtained from an impedance analyzer.Relevant parameters such as ac/dc conductivity,dielectric loss,dielectric constant,activation energy,dissipation factor and Cole-Cole impedance spectra were extensively evaluated for various Ga ion mole ratios in the substitution where x≤1.0.We notice that the ac conductivity mostly obeys exponential power law rules,which vary significantly with the substitution ratios of Ga ions.Impedance analyses confirm that differences in conduction mechanisms in NiCoGaFe-MSFs are mainly due to grain-to-grain boundaries related to Ga ion substitution ratios.The change in dielectric constant of NiCoGaFe-MSFs is strongly dependent on the substitution rates and results in a normal dielectric distribution with frequency.The tangential loss for all micro spheres is observed to vary with measured temperatures and their frequency dependencies can be attributed to the conduction mechanism similar to Koop’s phenomenological model.It is clearly seen that the formation of semicircles is dominated by all the NiCoGaFe-MSFs and the diameter of the semicircles mostly decreases with increasing temperature,as evidence of a temperaturedependent relaxation mechanism.展开更多
The CoTmx Fe2-x O4(x≤0.1) NPs were synthesized sonochemically.X-ray powder diffraction patterns and TEM images of the samples prove their chemical purity and cubic structure-morphology,respectively.Some substitution ...The CoTmx Fe2-x O4(x≤0.1) NPs were synthesized sonochemically.X-ray powder diffraction patterns and TEM images of the samples prove their chemical purity and cubic structure-morphology,respectively.Some substitution ratio of thulium ions to cobalt ferrites have an important effect on the characteristic evaluation of both electrical and dielectric characteristic measured at frequencies up to 3.0 MHz between room temperature and 120℃.Since the thulium substitution has a very strong effect on the characteristic evaluation of both electrical and dielectric properties of cobalt-ferrite samples,four substitutio nal ranges-none,small,medium and high were determined for the interpretation of contribution of thulium ratio to ac/dc conductivity,dielectric constant,dielectric loss and tangent loss.Conductivity increases with the incremental frequencies,in general depending on a variety of tendencies of both temperature and substitutional Tm ratios while the activation energy varies with a high dependency to the regional level of Tm substitution in Co-ferrites NPs.The Arrhenius graph appears to provide us with a single activation energy much higher than 400 meV for x=0.02,which can be attributed to electron hopping mechanisms,apart from other substituted spinel ferrites.展开更多
Purpose: To determine the stort-term effects of latano-prost (Xalatan) on the retrobulbar circulation and intraocular pressure (IOP) in ocular hypertension. Materials and Methods: Forty-six eyes of 23 consecutive ocul...Purpose: To determine the stort-term effects of latano-prost (Xalatan) on the retrobulbar circulation and intraocular pressure (IOP) in ocular hypertension. Materials and Methods: Forty-six eyes of 23 consecutive ocular hypertension patients older than 20 years. All patients had IOP greater than 22 mmHg. One eye of each patient was randomly selected to展开更多
文摘Microspheres of Ni_(0.5)Co_(0.5)Ga_(x)Fe_(2-x)O_(4)(x≤1.0)microsphere spinel ferrites(NiCoGaFe-MSFs)and carbon spheres were prepared via a hydrothermal technique.The micro structure of microspheres was investigated through scanning and transmission electron microscopy(SEM and TEM),respectively,and X-ray diffraction(XRD).The electrical and dielectric properties of NiCoGaFe-MSF at temperatures ranging from20 to 120℃(between 293,1×10^(3)and 393.1×10^(3))for f≤3.0 MHz were systematically studied as a result of 3D graphical drawing of the data obtained from an impedance analyzer.Relevant parameters such as ac/dc conductivity,dielectric loss,dielectric constant,activation energy,dissipation factor and Cole-Cole impedance spectra were extensively evaluated for various Ga ion mole ratios in the substitution where x≤1.0.We notice that the ac conductivity mostly obeys exponential power law rules,which vary significantly with the substitution ratios of Ga ions.Impedance analyses confirm that differences in conduction mechanisms in NiCoGaFe-MSFs are mainly due to grain-to-grain boundaries related to Ga ion substitution ratios.The change in dielectric constant of NiCoGaFe-MSFs is strongly dependent on the substitution rates and results in a normal dielectric distribution with frequency.The tangential loss for all micro spheres is observed to vary with measured temperatures and their frequency dependencies can be attributed to the conduction mechanism similar to Koop’s phenomenological model.It is clearly seen that the formation of semicircles is dominated by all the NiCoGaFe-MSFs and the diameter of the semicircles mostly decreases with increasing temperature,as evidence of a temperaturedependent relaxation mechanism.
基金The Institute for Research and Medical Consultations of Imam Abdulrahman Bin Faisal University (Saudi Arabia) is highly acknowledged for providing the supports through the Projects application No.2019-IRMC-S-1。
文摘The CoTmx Fe2-x O4(x≤0.1) NPs were synthesized sonochemically.X-ray powder diffraction patterns and TEM images of the samples prove their chemical purity and cubic structure-morphology,respectively.Some substitution ratio of thulium ions to cobalt ferrites have an important effect on the characteristic evaluation of both electrical and dielectric characteristic measured at frequencies up to 3.0 MHz between room temperature and 120℃.Since the thulium substitution has a very strong effect on the characteristic evaluation of both electrical and dielectric properties of cobalt-ferrite samples,four substitutio nal ranges-none,small,medium and high were determined for the interpretation of contribution of thulium ratio to ac/dc conductivity,dielectric constant,dielectric loss and tangent loss.Conductivity increases with the incremental frequencies,in general depending on a variety of tendencies of both temperature and substitutional Tm ratios while the activation energy varies with a high dependency to the regional level of Tm substitution in Co-ferrites NPs.The Arrhenius graph appears to provide us with a single activation energy much higher than 400 meV for x=0.02,which can be attributed to electron hopping mechanisms,apart from other substituted spinel ferrites.
文摘Purpose: To determine the stort-term effects of latano-prost (Xalatan) on the retrobulbar circulation and intraocular pressure (IOP) in ocular hypertension. Materials and Methods: Forty-six eyes of 23 consecutive ocular hypertension patients older than 20 years. All patients had IOP greater than 22 mmHg. One eye of each patient was randomly selected to
