Magnetic bubbles have again become a subject of significant attention following the experimental observation of topologically nontrivial magnetic skyrmions. In recent work, tailoring the shape of the bubbles is consid...Magnetic bubbles have again become a subject of significant attention following the experimental observation of topologically nontrivial magnetic skyrmions. In recent work, tailoring the shape of the bubbles is considered a key factor for their dynamics in spintronic devices. In addition to the reported circular, elliptical, and square bubbles, here we observe triangular bubble domains in bismuth-doped yttrium iron garnet(Bi-YIG) using Kerr microscopy. The bubble domains evolve from discrete circular to latticed triangular and hexagonal shapes. Further, the orientation of the triangular bubbles in the hexagonal lattices can be flipped by decreasing the magnetic field. The sixfold in-plane magnetic anisotropy of Bi-YIG(111) crystal, which is presumably the mechanism underlying the triangular shape of the bubbles, is measured as1179 erg/cm~3. The study of the morphologies of topologically trivial bubbles in YIG offers insight into nontrivial spin textures, which is appealing for future spintronic applications.展开更多
The valenceofelementyttrium of Y2 O3 Mocathode materialhasbeenstudied by usingther mal weight analysis, X ray diffraction analysis, Scanning electron microscopy and X rayphotoelectronspectrum . It hasbeen provedthatyt...The valenceofelementyttrium of Y2 O3 Mocathode materialhasbeenstudied by usingther mal weight analysis, X ray diffraction analysis, Scanning electron microscopy and X rayphotoelectronspectrum . It hasbeen provedthatyttrium oxidecan bereduced by molybdenum carbide. Thereaction between powdered Y2 O3 and Mo2 Ccan happen at 1173 , and Y2 O3may bereduced to metallicyttrium . Afterthepowder mixtureof Y2 O3 and Mo2 Cwasheat treated at1873 K, Yttrium existsin two kinds of chemicalstate- yttrium of zero valence and yttrium ofthreevalences.展开更多
The applicability of Ce and Y as promising candidate elements to form irreversible traps in weld metal was investigated by thermal desorption spectroscopy(TDS) with gas chromatography(GC). The precise nature of the pr...The applicability of Ce and Y as promising candidate elements to form irreversible traps in weld metal was investigated by thermal desorption spectroscopy(TDS) with gas chromatography(GC). The precise nature of the precipitate particles newly formed in the weld metal by the addition of Ce and Y to a certain alloy system was characterized. Moreover,the hydrogen trapping efficiency expressed as the reduction of the diffusible hydrogen in the weld metal was analyzed. The results showed that the addition of Ce and/or Y to this alloy system led to the formation of a mixed type of(Ce,Ti)-based oxide,(Y,Ni)-based carbide,or(Ce,Y,Ti)-based oxide particles. Because of the high activation energy of the mixed type of particles(≥ 150 k J/mol),the trapping efficiency for hydrogen was considered to be sufficiently high to effectively reduce the diffusible hydrogen content.展开更多
Y2O3 nanomaterials have been widely used in transparent ceramics and luminescent devices. Recently there are many studies focusing on controlling the size and morphology of Y2O3 in order to obtain better materials per...Y2O3 nanomaterials have been widely used in transparent ceramics and luminescent devices. Recently there are many studies focusing on controlling the size and morphology of Y2O3 in order to obtain better materials performance. In present study, yttrium oxyhydroxide precursor was synthesized via a facile solvothermal process through the dissolution-recrystallization mechanism of Y2O3 raw powders in the ethylenediamine solvent, then nanosized yttrium oxide crystal was prepared from the precursor through post heat treatment process. The effects of solvothermal treatment temperature, holding time, solvent kinds and post heat treatment parameters on crystalline structure, grain shape and size of nanocrystal were investigated by XRD, TEM and TGA-DTA measurements. TEM images reveal that the morphology of product after post heat treatment at 460 ℃ for 12 h is rice-like nanocrystal. XRD shows that this product is pure cubic Y2O3 cphase. Present study reveals that high purity Y2O3 with rice-like morphology can be easily prepared with average size around 30 nm under suitable post heat treatment parameters. In addition, the effects of solvents such as water and ethanol etc. on the crystal structure and morphology were also investigated. It is suggested that dissolution-recrystallization process may be the main mechanism for the formation of nano-sized YOOH precursors under solvothermal reaction condition, and the ethylenediamine solvent is likely to play an important role in controlling the transformation process of yttria precursors to theY2O3 nanocrystal.展开更多
The oridation resistance at 1100°C of a dirationally solidified Ni3Al base alloy IC6is substantially improved by the addition of yttriurn or yttrium and silicon. The stress rupture property under 1100°C/80MP...The oridation resistance at 1100°C of a dirationally solidified Ni3Al base alloy IC6is substantially improved by the addition of yttriurn or yttrium and silicon. The stress rupture property under 1100°C/80MPa is increased by adding proper amounts of yttrium, howevef it decreases bg adding 0.3wt% silicon and 0. 1wt% yttrium at the same time, which may be attributed to the formation of a needle like phase rich in nickel and molybdenum.展开更多
The effect of different amounts of rare earth element yttrium on the microstructure of the directionally solidified (DS) Ni 3Al base alloy IC6 was studied with scanning electron microscope(SEM). The results showed tha...The effect of different amounts of rare earth element yttrium on the microstructure of the directionally solidified (DS) Ni 3Al base alloy IC6 was studied with scanning electron microscope(SEM). The results showed that the microstructure of alloys with addition of 0.04%～0.12%Y had no obvious difference compared with that of IC6 without yttrium, and a bulk shape phase rich in Ni, Mo and Y was formed within large size γ′ phase in interdendritic area in the alloy with 0.20%Y, and the volume of large size γ′ phase in interdendritic area increased when the adding amounts of yttrium increased to 0.3%. The stress rupture properties at 1 100 ℃, 80 MPa were improved by adding 0.04%～0.20%Y. The oxidation resistance and thermal fatigue property of the alloys with different amounts of yttrium were tested at 1 100 ℃. The results showed that the oxidation resistance and thermal fatigue property were substantially improved by adding proper amounts of yttrium.展开更多
The rare earth elements and yttrium(REY)of the K2 coal from the Moxinpo mine,Chongqing,were determined using inductively coupled plasma mass spectrometry(ICP-MS).The results show that REY are enriched in the K2 coal,w...The rare earth elements and yttrium(REY)of the K2 coal from the Moxinpo mine,Chongqing,were determined using inductively coupled plasma mass spectrometry(ICP-MS).The results show that REY are enriched in the K2 coal,with the average content up to 462 lg/g,much higher than average values of most coals in the world.The REY distribution patterns indicate that the light REY is enriched and show a well-pronounced Eu minimum.The fractionation of individual light-REY is higher than that of the heavy-REY.The REY distribution through the K2 coal seam shows that the top and bottom portion of the coal seam have a lower content of REY than the middle portion.Goyazite and rhabdophane were identified with a scanning electron microscope equipped with an energy-dispersed X-ray spectrometer(SEM-EDX).The REY distributions through the coal seam,SEM-EDX data and the correlation analysis between ash yields and the concentrations have revealed that the REY mainly occurs in the organic matter.The K2 coal is a potential rare-metal resource due to its high REY contents,and the coal ash could be regarded as a new and promising raw material for recovery of REY as a by-product.展开更多
The influence of yttrium on the corrosion behavior of Mg–Y alloys has been investigated by electrochemical measurements,scanning electron microscope(SEM)observation,X-ray diffraction(XRD),and X-ray photoelectron spec...The influence of yttrium on the corrosion behavior of Mg–Y alloys has been investigated by electrochemical measurements,scanning electron microscope(SEM)observation,X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS)analysis in NaCl solution.The corrosion resistance decreased with increasing Y content due to increasing Y-rich zone.The solid-dissolved Y improved the chemical activity of the substrate which promoted the corrosion reaction by forming Y2O3.The corrosion resistance was improved by increasing the Y concentration of matrix and proper net Y-rich structure.The sample has the best corrosion resistance when all the Y element was dissolved into the matrix of Mg–5Y in 0.1 M NaCl.展开更多
The 1100 ℃ isothermal oxidation behavior of Fe 23Cr 5Al alloy modified by yttrium addition was studied by means of thermogravimetric analysis, scanning electron microscopy and energy dispersive X ray analysis. Yttriu...The 1100 ℃ isothermal oxidation behavior of Fe 23Cr 5Al alloy modified by yttrium addition was studied by means of thermogravimetric analysis, scanning electron microscopy and energy dispersive X ray analysis. Yttrium was added to this alloy in the forms of metallic addition, yttrium oxide and ion implant. Cracking and spalling occurred on the convoluted scale formed on Y free alloy and exposed the substrate. A flat dense scale without spallation was formed on the yttrium alloying addition or yttrium oxide dispersion alloy. The scale adhesion was also improved by 1×10 17 Y +/cm 2 implantation. The results indicate the convoluted morphology of the scale on Fe 23Cr 5Al 0 21Ti alloy is related to the growth mechanism of the alumina scale, and the spallation of the scale is related to sulfur segregation at the scale/alloy interface. The main reason that the adhesion of alumina scale is improved by yttrium addition lies in the following. Yttrium is liable to form a stable yttrium sulfide with sulfur in the alloy and prevent sulfur interface from segregation. Another reason is that the growth mechanism of alumina scale is changed by yttrium addition.展开更多
The interfacial behavior of sulfur and yttrium in the yttrium modified Ni 3Al based alloy IC6 during oxidation at 1100 ℃ was analyzed by X ray line scan of electron probe microstructural analysis(EPMA). The results s...The interfacial behavior of sulfur and yttrium in the yttrium modified Ni 3Al based alloy IC6 during oxidation at 1100 ℃ was analyzed by X ray line scan of electron probe microstructural analysis(EPMA). The results show that the migration and segregation of sulfur to the interface between oxide scale and the substrate at high temperature is retarded owing to the presence of yttrium. This is attributed to the desulfurization by yttrium in the melt and the trapping of sulfur by yttrium rich phases during oxidation, which leads to improving the coherence between oxide scale and substrate. Another reason of increasing the high temperature oxidation resistance of alloy IC6 by the addition of yttrium is that yttrium migrates to the grain boundaries of oxides during oxidation and hence improve their strength. This results in the transformation of the oxide scale spallation cracks from intergranular cracks for alloy without yttrium to transgranular ones for yttrium modified alloy.展开更多
The mechanical properties of metal yttrium such as strength, plasticity, hardness and elasticity were introduced. The purifying techniques of yttrium were discussed in detail. The processing methods for metal yttrium ...The mechanical properties of metal yttrium such as strength, plasticity, hardness and elasticity were introduced. The purifying techniques of yttrium were discussed in detail. The processing methods for metal yttrium including extruding, forging, rolling, wiredrawing and welding were also introduced. Finally, the potential use of yttrium and its alloys were prospected.展开更多
Tetraethylenepentamine(C8H23N5,TEPA) has been used as a novel precipitant to synthesize yttrium aluminum garnet(Y3Al5O12,YAG) precursor from a mixed solution of aluminum and yttrium nitrates via a normal-strike co-pre...Tetraethylenepentamine(C8H23N5,TEPA) has been used as a novel precipitant to synthesize yttrium aluminum garnet(Y3Al5O12,YAG) precursor from a mixed solution of aluminum and yttrium nitrates via a normal-strike co-precipitation method without controlling the pH value during precipitation process.The original precursor was analyzed by thermogravimetry/differential scanning calorimetry(TG/DSC).The evolution of phase composition and micro-structure of the as-synthesized YAG powders were characterized by X-ray diffraction(XRD),Fourier transform infrared(FT-IR) spectroscopy and transmission electron microscopy(TEM).Compositionally pure YAG nanostructured powders were directly obtained by calcination of the precursor at 900 ℃ without the formation of any intermediate phases.The average particle size determined from TEM micrograph for the powder obtained at 1000 ℃ was approximately 50 nm.展开更多
Transarterial radioembolization(TARE) is a form of brachytherapy in which intra-arterially injected yttrium-90-loaded microspheres serve as a source for internal radiation purposes.On the average,it produces disease c...Transarterial radioembolization(TARE) is a form of brachytherapy in which intra-arterially injected yttrium-90-loaded microspheres serve as a source for internal radiation purposes.On the average,it produces disease control rates exceeding 80% and it is a consolidated therapy for hepatocellular carcinoma(HCC);however,current data are all based on retrospective series or non-controlled prospective studies since randomized controlled trials comparing it with the other liver-directed therapies for intermediate and locally advanced stage HCC are still underway.The data available show that TARE provides similar or even better survival rates when compared to transarterial chemoembolization(TACE).First-line TARE is best indicated for both intermediatestage patients(staged according to the barcelona clinic liver cancer staging classification) who have lesions which respond poorly to TACE due to multiple tumors or a large tumor burden,and for locally advanced-stage patients with solitary tumors,and segmental or lobar portal vein tumor thrombosis.In addition,emerging data have suggested the use of TARE in patients who are classified slightly beyond the Milan criteria regarding radical treatment for downstaging purposes.As a secondline treatment,TARE can also be applied in patients progressing to TACE or sorafenib;a large number of phase Ⅱ/Ⅲ trials are ongoing with the purpose of evaluating the best association with systemic therapies.Transarterial radioembolization is very well tolerated and has a low rate of complications which are mainly related to unintended non-target tissue irradiation,including the surrounding liver parenchyma.The complications can be additionally reduced by accurate patient selection and a strict pre-treatment evaluation including dosimetry and assessment of the vascular anatomy.Since a correct treatment algorithm for potential TARE candidates is not clear and standardized,this comprehensive review analyzes the best selection criteria for patients who really benefit from TARE and also the new advances of this therapy,which can be a very important weapon against HCC.展开更多
The microstructures and corrosion behaviors of Mg-6%Al-3%Zn and Mg-6%Al-3%Zn-(0.251.0)%Y in 3.5 wt.%Na Cl solution are investigated via morphology observation,phase characterization,immersion and electrochemical metho...The microstructures and corrosion behaviors of Mg-6%Al-3%Zn and Mg-6%Al-3%Zn-(0.251.0)%Y in 3.5 wt.%Na Cl solution are investigated via morphology observation,phase characterization,immersion and electrochemical methods.The experimental results suggest that yttrium alloying can improve the corrosion resistance of Mg-6%Al-3%Zn throughout the immersion.The initial enhanced corrosion resistance of magnesium alloy is attributed to the Y alloying,which gives rise to the increasing content of Al_(2)O_(3)in oxide layer.The promoted protectiveness of oxide layer on Mg-6%Al-3%Zn-1.0%Y alloy arouse a filiform corrosion as revealed by in-situ metallographic observation.Furthermore,the Y-containing magnesium alloys still perform higher corrosion resistance compared with that of Mg-6%Al-3%Zn alloy even if the oxide layer is exhausted.This phenomenon is owing to two factors,one is the gradual transformation of intermetallic phases from continuous Mg_(17)Al_(12)to discrete Al_(2)Y in matrix,by which the micro-galvanic corrosion betweenα-Mg grains and intermetallic phases is alleviated;the other is the morphology variation of corrosion products,the uniform and compact products layer on Y-containing alloys provide a barrier that effectively prevent the corrosive ions from penetrating into and reacting with Mg matrix.展开更多
基金support by the National Natural Science Foundation of China (Grant Nos. 52061135105 and 12074025)support by the National Natural Science Foundation of China (Grant Nos. 11974079, 12274083, and 12221004)the Shanghai Municipal Science and Technology Basic Research Project (Grant No. 22JC1400200)。
文摘Magnetic bubbles have again become a subject of significant attention following the experimental observation of topologically nontrivial magnetic skyrmions. In recent work, tailoring the shape of the bubbles is considered a key factor for their dynamics in spintronic devices. In addition to the reported circular, elliptical, and square bubbles, here we observe triangular bubble domains in bismuth-doped yttrium iron garnet(Bi-YIG) using Kerr microscopy. The bubble domains evolve from discrete circular to latticed triangular and hexagonal shapes. Further, the orientation of the triangular bubbles in the hexagonal lattices can be flipped by decreasing the magnetic field. The sixfold in-plane magnetic anisotropy of Bi-YIG(111) crystal, which is presumably the mechanism underlying the triangular shape of the bubbles, is measured as1179 erg/cm~3. The study of the morphologies of topologically trivial bubbles in YIG offers insight into nontrivial spin textures, which is appealing for future spintronic applications.
文摘The valenceofelementyttrium of Y2 O3 Mocathode materialhasbeenstudied by usingther mal weight analysis, X ray diffraction analysis, Scanning electron microscopy and X rayphotoelectronspectrum . It hasbeen provedthatyttrium oxidecan bereduced by molybdenum carbide. Thereaction between powdered Y2 O3 and Mo2 Ccan happen at 1173 , and Y2 O3may bereduced to metallicyttrium . Afterthepowder mixtureof Y2 O3 and Mo2 Cwasheat treated at1873 K, Yttrium existsin two kinds of chemicalstate- yttrium of zero valence and yttrium ofthreevalences.
文摘The applicability of Ce and Y as promising candidate elements to form irreversible traps in weld metal was investigated by thermal desorption spectroscopy(TDS) with gas chromatography(GC). The precise nature of the precipitate particles newly formed in the weld metal by the addition of Ce and Y to a certain alloy system was characterized. Moreover,the hydrogen trapping efficiency expressed as the reduction of the diffusible hydrogen in the weld metal was analyzed. The results showed that the addition of Ce and/or Y to this alloy system led to the formation of a mixed type of(Ce,Ti)-based oxide,(Y,Ni)-based carbide,or(Ce,Y,Ti)-based oxide particles. Because of the high activation energy of the mixed type of particles(≥ 150 k J/mol),the trapping efficiency for hydrogen was considered to be sufficiently high to effectively reduce the diffusible hydrogen content.
基金Project supported by SRF for ROCS, SEM (2003-14) and Science and Technology Department of Zhejiang Province (2003C11027)
文摘Y2O3 nanomaterials have been widely used in transparent ceramics and luminescent devices. Recently there are many studies focusing on controlling the size and morphology of Y2O3 in order to obtain better materials performance. In present study, yttrium oxyhydroxide precursor was synthesized via a facile solvothermal process through the dissolution-recrystallization mechanism of Y2O3 raw powders in the ethylenediamine solvent, then nanosized yttrium oxide crystal was prepared from the precursor through post heat treatment process. The effects of solvothermal treatment temperature, holding time, solvent kinds and post heat treatment parameters on crystalline structure, grain shape and size of nanocrystal were investigated by XRD, TEM and TGA-DTA measurements. TEM images reveal that the morphology of product after post heat treatment at 460 ℃ for 12 h is rice-like nanocrystal. XRD shows that this product is pure cubic Y2O3 cphase. Present study reveals that high purity Y2O3 with rice-like morphology can be easily prepared with average size around 30 nm under suitable post heat treatment parameters. In addition, the effects of solvents such as water and ethanol etc. on the crystal structure and morphology were also investigated. It is suggested that dissolution-recrystallization process may be the main mechanism for the formation of nano-sized YOOH precursors under solvothermal reaction condition, and the ethylenediamine solvent is likely to play an important role in controlling the transformation process of yttria precursors to theY2O3 nanocrystal.
文摘The oridation resistance at 1100°C of a dirationally solidified Ni3Al base alloy IC6is substantially improved by the addition of yttriurn or yttrium and silicon. The stress rupture property under 1100°C/80MPa is increased by adding proper amounts of yttrium, howevef it decreases bg adding 0.3wt% silicon and 0. 1wt% yttrium at the same time, which may be attributed to the formation of a needle like phase rich in nickel and molybdenum.
文摘The effect of different amounts of rare earth element yttrium on the microstructure of the directionally solidified (DS) Ni 3Al base alloy IC6 was studied with scanning electron microscope(SEM). The results showed that the microstructure of alloys with addition of 0.04%～0.12%Y had no obvious difference compared with that of IC6 without yttrium, and a bulk shape phase rich in Ni, Mo and Y was formed within large size γ′ phase in interdendritic area in the alloy with 0.20%Y, and the volume of large size γ′ phase in interdendritic area increased when the adding amounts of yttrium increased to 0.3%. The stress rupture properties at 1 100 ℃, 80 MPa were improved by adding 0.04%～0.20%Y. The oxidation resistance and thermal fatigue property of the alloys with different amounts of yttrium were tested at 1 100 ℃. The results showed that the oxidation resistance and thermal fatigue property were substantially improved by adding proper amounts of yttrium.
基金This research was supported by the National Key Basic Research and Development Program(No.2014CB238902)National Natural Science Foundation of China(No.41302128).
文摘The rare earth elements and yttrium(REY)of the K2 coal from the Moxinpo mine,Chongqing,were determined using inductively coupled plasma mass spectrometry(ICP-MS).The results show that REY are enriched in the K2 coal,with the average content up to 462 lg/g,much higher than average values of most coals in the world.The REY distribution patterns indicate that the light REY is enriched and show a well-pronounced Eu minimum.The fractionation of individual light-REY is higher than that of the heavy-REY.The REY distribution through the K2 coal seam shows that the top and bottom portion of the coal seam have a lower content of REY than the middle portion.Goyazite and rhabdophane were identified with a scanning electron microscope equipped with an energy-dispersed X-ray spectrometer(SEM-EDX).The REY distributions through the coal seam,SEM-EDX data and the correlation analysis between ash yields and the concentrations have revealed that the REY mainly occurs in the organic matter.The K2 coal is a potential rare-metal resource due to its high REY contents,and the coal ash could be regarded as a new and promising raw material for recovery of REY as a by-product.
基金the National Basic Research Program of China(grant number:2013CB632205)National Natural Science Foundation of China(grant number:51501199).
文摘The influence of yttrium on the corrosion behavior of Mg–Y alloys has been investigated by electrochemical measurements,scanning electron microscope(SEM)observation,X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS)analysis in NaCl solution.The corrosion resistance decreased with increasing Y content due to increasing Y-rich zone.The solid-dissolved Y improved the chemical activity of the substrate which promoted the corrosion reaction by forming Y2O3.The corrosion resistance was improved by increasing the Y concentration of matrix and proper net Y-rich structure.The sample has the best corrosion resistance when all the Y element was dissolved into the matrix of Mg–5Y in 0.1 M NaCl.
文摘The 1100 ℃ isothermal oxidation behavior of Fe 23Cr 5Al alloy modified by yttrium addition was studied by means of thermogravimetric analysis, scanning electron microscopy and energy dispersive X ray analysis. Yttrium was added to this alloy in the forms of metallic addition, yttrium oxide and ion implant. Cracking and spalling occurred on the convoluted scale formed on Y free alloy and exposed the substrate. A flat dense scale without spallation was formed on the yttrium alloying addition or yttrium oxide dispersion alloy. The scale adhesion was also improved by 1×10 17 Y +/cm 2 implantation. The results indicate the convoluted morphology of the scale on Fe 23Cr 5Al 0 21Ti alloy is related to the growth mechanism of the alumina scale, and the spallation of the scale is related to sulfur segregation at the scale/alloy interface. The main reason that the adhesion of alumina scale is improved by yttrium addition lies in the following. Yttrium is liable to form a stable yttrium sulfide with sulfur in the alloy and prevent sulfur interface from segregation. Another reason is that the growth mechanism of alumina scale is changed by yttrium addition.
文摘The interfacial behavior of sulfur and yttrium in the yttrium modified Ni 3Al based alloy IC6 during oxidation at 1100 ℃ was analyzed by X ray line scan of electron probe microstructural analysis(EPMA). The results show that the migration and segregation of sulfur to the interface between oxide scale and the substrate at high temperature is retarded owing to the presence of yttrium. This is attributed to the desulfurization by yttrium in the melt and the trapping of sulfur by yttrium rich phases during oxidation, which leads to improving the coherence between oxide scale and substrate. Another reason of increasing the high temperature oxidation resistance of alloy IC6 by the addition of yttrium is that yttrium migrates to the grain boundaries of oxides during oxidation and hence improve their strength. This results in the transformation of the oxide scale spallation cracks from intergranular cracks for alloy without yttrium to transgranular ones for yttrium modified alloy.
文摘The mechanical properties of metal yttrium such as strength, plasticity, hardness and elasticity were introduced. The purifying techniques of yttrium were discussed in detail. The processing methods for metal yttrium including extruding, forging, rolling, wiredrawing and welding were also introduced. Finally, the potential use of yttrium and its alloys were prospected.
文摘Tetraethylenepentamine(C8H23N5,TEPA) has been used as a novel precipitant to synthesize yttrium aluminum garnet(Y3Al5O12,YAG) precursor from a mixed solution of aluminum and yttrium nitrates via a normal-strike co-precipitation method without controlling the pH value during precipitation process.The original precursor was analyzed by thermogravimetry/differential scanning calorimetry(TG/DSC).The evolution of phase composition and micro-structure of the as-synthesized YAG powders were characterized by X-ray diffraction(XRD),Fourier transform infrared(FT-IR) spectroscopy and transmission electron microscopy(TEM).Compositionally pure YAG nanostructured powders were directly obtained by calcination of the precursor at 900 ℃ without the formation of any intermediate phases.The average particle size determined from TEM micrograph for the powder obtained at 1000 ℃ was approximately 50 nm.
文摘Transarterial radioembolization(TARE) is a form of brachytherapy in which intra-arterially injected yttrium-90-loaded microspheres serve as a source for internal radiation purposes.On the average,it produces disease control rates exceeding 80% and it is a consolidated therapy for hepatocellular carcinoma(HCC);however,current data are all based on retrospective series or non-controlled prospective studies since randomized controlled trials comparing it with the other liver-directed therapies for intermediate and locally advanced stage HCC are still underway.The data available show that TARE provides similar or even better survival rates when compared to transarterial chemoembolization(TACE).First-line TARE is best indicated for both intermediatestage patients(staged according to the barcelona clinic liver cancer staging classification) who have lesions which respond poorly to TACE due to multiple tumors or a large tumor burden,and for locally advanced-stage patients with solitary tumors,and segmental or lobar portal vein tumor thrombosis.In addition,emerging data have suggested the use of TARE in patients who are classified slightly beyond the Milan criteria regarding radical treatment for downstaging purposes.As a secondline treatment,TARE can also be applied in patients progressing to TACE or sorafenib;a large number of phase Ⅱ/Ⅲ trials are ongoing with the purpose of evaluating the best association with systemic therapies.Transarterial radioembolization is very well tolerated and has a low rate of complications which are mainly related to unintended non-target tissue irradiation,including the surrounding liver parenchyma.The complications can be additionally reduced by accurate patient selection and a strict pre-treatment evaluation including dosimetry and assessment of the vascular anatomy.Since a correct treatment algorithm for potential TARE candidates is not clear and standardized,this comprehensive review analyzes the best selection criteria for patients who really benefit from TARE and also the new advances of this therapy,which can be a very important weapon against HCC.
基金financial support of the Natural Science Foundation of Shan Dong Province of China(Grant No.ZR2018BD025)National Natural Science Foundation of China(Grant No.41576114)+2 种基金Qingdao Innovative Leading Talent Foundation(Grant No.15-10-3-15-(39)zch)Qingdao Science and Technology Achievement Transformation Guidance Plan(Applied Basic Research,Grant No.14-2-4-4-jch)financially supported by State Key Laboratory for Marine Corrosion and Protection,Luoyang Ship Material Research Institute,China(Project No.KF190404)
文摘The microstructures and corrosion behaviors of Mg-6%Al-3%Zn and Mg-6%Al-3%Zn-(0.251.0)%Y in 3.5 wt.%Na Cl solution are investigated via morphology observation,phase characterization,immersion and electrochemical methods.The experimental results suggest that yttrium alloying can improve the corrosion resistance of Mg-6%Al-3%Zn throughout the immersion.The initial enhanced corrosion resistance of magnesium alloy is attributed to the Y alloying,which gives rise to the increasing content of Al_(2)O_(3)in oxide layer.The promoted protectiveness of oxide layer on Mg-6%Al-3%Zn-1.0%Y alloy arouse a filiform corrosion as revealed by in-situ metallographic observation.Furthermore,the Y-containing magnesium alloys still perform higher corrosion resistance compared with that of Mg-6%Al-3%Zn alloy even if the oxide layer is exhausted.This phenomenon is owing to two factors,one is the gradual transformation of intermetallic phases from continuous Mg_(17)Al_(12)to discrete Al_(2)Y in matrix,by which the micro-galvanic corrosion betweenα-Mg grains and intermetallic phases is alleviated;the other is the morphology variation of corrosion products,the uniform and compact products layer on Y-containing alloys provide a barrier that effectively prevent the corrosive ions from penetrating into and reacting with Mg matrix.
