In this work we are interested in studying the effect of the heat treatments on the dopant segregation at the grain boundaries in the polycrystalline silicon films. The obtained results have shown that the heat treatm...In this work we are interested in studying the effect of the heat treatments on the dopant segregation at the grain boundaries in the polycrystalline silicon films. The obtained results have shown that the heat treatments reduce the number of segregation sites at the grains boundaries, and consequently they limit the structural changes that can appear there and the quantity of the dope atoms that can accumulate in these boundaries. In addition they are more and more dopant that are found inside the grains when the temperature of the heat treatment increases. On the other hand, we established that the arsenic atoms have a strong tendency to the segregation than the boron atoms, and we have noticed a strong migration of arsenic atoms from the boundaries towards the grains under the effect of the heat treatments. It was also shown that the segregation of arsenic atoms at the grains boundaries is about 4 times higher than that of the boron atoms.展开更多
It has presented a review of the results of the survey on the formation and behavior of submicropores (SMP) in mono- and poly-crystalline systems, condensed in the “open vacuum” and quasi-closed volume. The mechanis...It has presented a review of the results of the survey on the formation and behavior of submicropores (SMP) in mono- and poly-crystalline systems, condensed in the “open vacuum” and quasi-closed volume. The mechanisms, patterns and characteristics of these processes, depending on the physical and technological factors are reviewed.展开更多
In regenerative medicine,a scaffold is needed to provide physical support for the growth of cells at the injury site.Carbon composites are also widely used in biomedicine.This research aimed to see if(MoWCu)S/rGO coul...In regenerative medicine,a scaffold is needed to provide physical support for the growth of cells at the injury site.Carbon composites are also widely used in biomedicine.This research aimed to see if(MoWCu)S/rGO could be used in peripheral and central neural regeneration as a carbon-based nanomaterial.This material was created using a one-step hydrothermal process.We used Scanning Electron Microscopy with Energy Dispersive X-ray analysis(SEM–EDX),X-ray diffraction,and Field-Emission Scanning Electron Microscopy(FE-SEM)to describe it.The researchers used animal models of spinal cord injury and sciatic nerve injury to assess its effect as a scaffold of anti-inflammatory and electrical conductivity.The Basso Beattie Bresnahan locomotor rating scale and von Frey Filament were used to assess neuronal function after(MoWCu)S/rGO transplantation.In addition,the expression of p75 NTR and neurotrophic factors(BDNF,NT3,and NGF)mRNA in the experimental rats nerve was compared to the normal ones using Real-Time RT-qPCR.In the experimental groups,the use of(MoWCu)S/rGO resulted in a significant increase in neurotrophic factor gene expression,while p75 NTR was inversely decreased.In conclusion,we found that the nerve regeneration activity of the(MoWCu)S/rGO scaffold in rat models significantly increased motor function recovery in the treated groups.Furthermore,the current study explained the response of this composite to inflammatory neurodegenerative diseases.(MoWCu)S incorporation in graphene is thought to have excellent properties and may be used in regenerative medicine.展开更多
This article represents a pioneering study centered on the corrosion kinetics of untreated and thermally processed mechano-synthesized Al_(x)Cr_(y)Ni_(z) two-dimensional decagonal quasicrystalline structure and crysta...This article represents a pioneering study centered on the corrosion kinetics of untreated and thermally processed mechano-synthesized Al_(x)Cr_(y)Ni_(z) two-dimensional decagonal quasicrystalline structure and crystalline approximants.It sheds light on the distinguished corrosion behavior of untreated and heat-treated mechano-synthesized Al_(72)Cr_(15)Ni_(13) and Al_(86)Cr_(12)Ni_(2)alloys,including a wide diversity of miscellaneous intermetallic phases.A comprehensive characterization was performed to analyze crystallographic structure and thermal characteristics of Al_(x)Cr_(y)Ni_(z) powder particles.Electrochemical evaluations of the mechano-synthesized Al_(72)Cr_(15)Ni_(13) and Al_(86)Cr_(12)Ni_(2) specimens and their heat-treated counterparts were conducted under cyclic potentiodynamic polarization tests with 0.1 mol/L Na_(2)SO_(4)(pH=2) and 3.5%NaCl(pH=8.5) electrolytes at room temperature,respectively.Al_(72)Cr_(15)Ni_(13) two-dimensional decagonal quasicrystalline phase was attained following 6 h mechanosynthesis and subsequent annealing treatment at 1035℃.There is no evidence of quasicrystal formation in the Al_(86)Cr_(12)Ni_(2) alloy system after 6 h mechano-synthesis and successive thermal processing at 445 and 570℃.In this study,we conducted the first investigation into electrochemical performance of both Al_(72)Cr_(15)Ni_(13) and Al_(86)Cr_(12)Ni_(2) intermetallics.Both Al_(72)Cr_(15)Ni_(13) and Al_(86)Cr_(12)Ni_(2) alloys develop a protective passive film in 0.1 mol/L Na_(2)SO_(4) electrolyte.It was determined that 6 h mechano-synthesized Al_(72)Cr_(15)Ni_(13) sample,subjected to annealing at 1035℃,stands out in the Al-Cr-Ni alloy systems for applications necessitating exceptional corrosion resistance,passivation behavior,and minimal susceptibility to pitting corrosion when compared to other tested counterparts.This alloy is characterized by a corrosion current density of 3.73μA/cm^(2) and a corrosion potential of-0.16 V(vs.Ag/AgCl),revealing a remarkably stable passive film up to a current density of 0.02 A/cm^(2) and a potential of 2.41 V(vs.Ag/AgCl)within 0.1 mol/L Na_(2)SO_(4) medium.Likewise,it exhibited a drastically diminished corrosion current density of 11.65μA/cm^(2) and a reduced corrosion potential of-0.27 V(vs.Ag/AgCl)within 3.5%NaCl electrolyte,attributed to the formation of two-dimensional decagonal quasicrystalline phase and hexagonalδ-Al_(3)Ni_(2) crystalline approximant at 1035℃.It also encompassed a re-passivation current density and potential of 50.35μA/cm^(2)and-0.04 V(vs.Ag/AgCl),respectively,within the latter solution.Its corrosion mechanism may be ascribed to a two-step surface precipitation process:initially,Al dissolves into a hydroxide,succeeded by the formation and precipitation of Al oxides,such as NaAlO_(2) and Al_(2)O_(3)·xH_(2)O.展开更多
A new small-signal model for anisomerous AlGaN/GaN high electron mobility transistors（HEMTs） is proposed for accurate prediction of HEMT behavior up to 20 GHz.The parasitic elements are extracted from both cold-FET ...A new small-signal model for anisomerous AlGaN/GaN high electron mobility transistors（HEMTs） is proposed for accurate prediction of HEMT behavior up to 20 GHz.The parasitic elements are extracted from both cold-FET and pinch-off bias to obtain more precise results and the intrinsic part is directly extracted.All the parameters needed in this process are determined by the device structure rather than optimization methods.This guarantees consistency between the parameter values and the component＇s physical meaning.展开更多
文摘In this work we are interested in studying the effect of the heat treatments on the dopant segregation at the grain boundaries in the polycrystalline silicon films. The obtained results have shown that the heat treatments reduce the number of segregation sites at the grains boundaries, and consequently they limit the structural changes that can appear there and the quantity of the dope atoms that can accumulate in these boundaries. In addition they are more and more dopant that are found inside the grains when the temperature of the heat treatment increases. On the other hand, we established that the arsenic atoms have a strong tendency to the segregation than the boron atoms, and we have noticed a strong migration of arsenic atoms from the boundaries towards the grains under the effect of the heat treatments. It was also shown that the segregation of arsenic atoms at the grains boundaries is about 4 times higher than that of the boron atoms.
文摘It has presented a review of the results of the survey on the formation and behavior of submicropores (SMP) in mono- and poly-crystalline systems, condensed in the “open vacuum” and quasi-closed volume. The mechanisms, patterns and characteristics of these processes, depending on the physical and technological factors are reviewed.
文摘In regenerative medicine,a scaffold is needed to provide physical support for the growth of cells at the injury site.Carbon composites are also widely used in biomedicine.This research aimed to see if(MoWCu)S/rGO could be used in peripheral and central neural regeneration as a carbon-based nanomaterial.This material was created using a one-step hydrothermal process.We used Scanning Electron Microscopy with Energy Dispersive X-ray analysis(SEM–EDX),X-ray diffraction,and Field-Emission Scanning Electron Microscopy(FE-SEM)to describe it.The researchers used animal models of spinal cord injury and sciatic nerve injury to assess its effect as a scaffold of anti-inflammatory and electrical conductivity.The Basso Beattie Bresnahan locomotor rating scale and von Frey Filament were used to assess neuronal function after(MoWCu)S/rGO transplantation.In addition,the expression of p75 NTR and neurotrophic factors(BDNF,NT3,and NGF)mRNA in the experimental rats nerve was compared to the normal ones using Real-Time RT-qPCR.In the experimental groups,the use of(MoWCu)S/rGO resulted in a significant increase in neurotrophic factor gene expression,while p75 NTR was inversely decreased.In conclusion,we found that the nerve regeneration activity of the(MoWCu)S/rGO scaffold in rat models significantly increased motor function recovery in the treated groups.Furthermore,the current study explained the response of this composite to inflammatory neurodegenerative diseases.(MoWCu)S incorporation in graphene is thought to have excellent properties and may be used in regenerative medicine.
文摘This article represents a pioneering study centered on the corrosion kinetics of untreated and thermally processed mechano-synthesized Al_(x)Cr_(y)Ni_(z) two-dimensional decagonal quasicrystalline structure and crystalline approximants.It sheds light on the distinguished corrosion behavior of untreated and heat-treated mechano-synthesized Al_(72)Cr_(15)Ni_(13) and Al_(86)Cr_(12)Ni_(2)alloys,including a wide diversity of miscellaneous intermetallic phases.A comprehensive characterization was performed to analyze crystallographic structure and thermal characteristics of Al_(x)Cr_(y)Ni_(z) powder particles.Electrochemical evaluations of the mechano-synthesized Al_(72)Cr_(15)Ni_(13) and Al_(86)Cr_(12)Ni_(2) specimens and their heat-treated counterparts were conducted under cyclic potentiodynamic polarization tests with 0.1 mol/L Na_(2)SO_(4)(pH=2) and 3.5%NaCl(pH=8.5) electrolytes at room temperature,respectively.Al_(72)Cr_(15)Ni_(13) two-dimensional decagonal quasicrystalline phase was attained following 6 h mechanosynthesis and subsequent annealing treatment at 1035℃.There is no evidence of quasicrystal formation in the Al_(86)Cr_(12)Ni_(2) alloy system after 6 h mechano-synthesis and successive thermal processing at 445 and 570℃.In this study,we conducted the first investigation into electrochemical performance of both Al_(72)Cr_(15)Ni_(13) and Al_(86)Cr_(12)Ni_(2) intermetallics.Both Al_(72)Cr_(15)Ni_(13) and Al_(86)Cr_(12)Ni_(2) alloys develop a protective passive film in 0.1 mol/L Na_(2)SO_(4) electrolyte.It was determined that 6 h mechano-synthesized Al_(72)Cr_(15)Ni_(13) sample,subjected to annealing at 1035℃,stands out in the Al-Cr-Ni alloy systems for applications necessitating exceptional corrosion resistance,passivation behavior,and minimal susceptibility to pitting corrosion when compared to other tested counterparts.This alloy is characterized by a corrosion current density of 3.73μA/cm^(2) and a corrosion potential of-0.16 V(vs.Ag/AgCl),revealing a remarkably stable passive film up to a current density of 0.02 A/cm^(2) and a potential of 2.41 V(vs.Ag/AgCl)within 0.1 mol/L Na_(2)SO_(4) medium.Likewise,it exhibited a drastically diminished corrosion current density of 11.65μA/cm^(2) and a reduced corrosion potential of-0.27 V(vs.Ag/AgCl)within 3.5%NaCl electrolyte,attributed to the formation of two-dimensional decagonal quasicrystalline phase and hexagonalδ-Al_(3)Ni_(2) crystalline approximant at 1035℃.It also encompassed a re-passivation current density and potential of 50.35μA/cm^(2)and-0.04 V(vs.Ag/AgCl),respectively,within the latter solution.Its corrosion mechanism may be ascribed to a two-step surface precipitation process:initially,Al dissolves into a hydroxide,succeeded by the formation and precipitation of Al oxides,such as NaAlO_(2) and Al_(2)O_(3)·xH_(2)O.
文摘A new small-signal model for anisomerous AlGaN/GaN high electron mobility transistors（HEMTs） is proposed for accurate prediction of HEMT behavior up to 20 GHz.The parasitic elements are extracted from both cold-FET and pinch-off bias to obtain more precise results and the intrinsic part is directly extracted.All the parameters needed in this process are determined by the device structure rather than optimization methods.This guarantees consistency between the parameter values and the component＇s physical meaning.
