Sm、Ce单掺以及Sm、Ce共掺CaO-B_2O_3-SiO_2玻璃中稀土离子的荧光性质研究

分别研究了单掺Sm2O3和CeO2以及共掺Sm2O3、CeO2的CaO-SiO2-B2O3玻璃的发光性质。单掺Sm2O3的CaO-SiO2-B2O3玻璃的光谱中出现典型的Sm3+的光谱性质;单掺CeO2的CaO-SiO2-B2O3玻璃的光谱中出现Ce3+的光谱性质,在332nm激发下,Ce3+发射蓝紫光,其发射光谱为一宽谱带,从350nm延展到500nm附近,主发射峰位于393nm,Stokes位移为61nm,只形成一个发光中心。当CaO-SiO2-B2O3玻璃共掺Sm2O3和CeO2时,出现Ce4+的发射峰,同时Sm3+的发光强度下降,说明作为一种新的激活剂Ce引入基质后,提高了Sm3+的局部对称性,Sm3+的f→f跃迁减弱,从而导致Sm3+的发光强度下降。在共掺Sm2O3、CeO2的CaO-SiO2-B2O3玻璃中Ce4+和Sm3+通过桥氧键相连。     

Influence of Composition of Sm2O3-Containing Rare Earth Glass on Its Absorption Spectrum

Lanthanidemetalsarethe 5 7thto 71thelementsintheperiodictable ,thetrivalentionsforlanthanideareofvalenceelectronshell 4f0～ 14 6s2 ,whicharefairlystablewhenthe 4felectronsub layerisemptyoral mostempty ,halffullorfull .Becauseofbigenergydifferencebetweenba…     

Optical Spectroscopy of Er^3＋ and Er^3＋/Yb^3＋ Co-doped Bi2O3-GeO2-B2O3-ZnO Glasses

The （60 - x）Bi2O3 - xGeO2-30B2O3-10ZnO （x = 5, 10, 20, 30 molar percent） glasses doped with Er^3＋ and Er^3＋/Yb^3＋ were fabricated using the melting method. The thermal stability of the glasses was studied with their DTA curves. The results show that the difference between the glass transition temperature and the crystallization onset temperature increases with the increase of GeO2 content, indicating that the thermal stability of the glass has become better. The absorption spectra were recorded and the stimulated emission cross sections were calculated using the McCumber theory. The Ω2, O4, and Ω6 parameters,the transition probability, the radiative lifetime, and the fluorescence branch ratio of Er^3＋ for optical transition were calculated from their absorption spectra in terms of reduced matrix U^（t）（λ = 2, 4, 6） character for optical transitions. The infrared emission of Er^3＋ was measured upon excitation with 970 nm light and the full width at half-maximum （FWHM） was estimated from the emission spectra. The pumping efficiency and the intensity of the emission at the 1.54 μm band of Er^3＋ were enhanced considerably by co-doping Yb^3＋ .     

Research on Glass Forming Ability of Er2O3 -Al2O3 -B2O3 -SiO2 System

The glass forming range of Er2O3-Al2O3-B2O3-SiO2 system was explored, and the effect of the content of Al2 O3 and Er2 O3 on glass-forming region was experimentally examined. It is shown that the region of glass formation range expends when the content of Al2O3 is changed from 15% to 20%, while it shrinks when the content of Er2O3 is changed from 20% to 30%. At the same time, the glass forming ability of Er2O3-Al2O3-B2O3-SiO2 system was also discussed using a value of β, which is an indication of crystallization tendency of glasses, calculated from thermo-analysis data. It is found that the glass forming ability of Er2O3-Al2O3-B2O3- SiO2 glasses is poor, while the glasses network may be enhanced when Al2O3 is added to the system, the glass forming ability being heightened. In addition, the crystallization temperatures of the rare earth glasses were determined using differential thermal analysis technique. The Er2O3-Al2O;-B2O3-SiO2 glass samples were heat treated at 1000,1100 and 1260℃ respectively. The results show that it is the Er2O3 phase that separates out from the glasses after crystaline heat treatment, and it is tiered up in glasses, as detected through XRD and SEM. This indicates that the phase separation occurs when the glasses are heated, Er3 being mainly distributed in the boron rich phase, then separated out from glasses, while the silicate rich phase remaining glassy state.     

Sm~(3+)掺杂ZnO-SiO_2-B_2O_3系微晶玻璃的制备及发光性能的研究

通过高温熔融法制备了ZnO-SiO2-B2O3:Sm3+系微晶玻璃,并采用SEM、XRD及荧光光谱仪研究了该微晶玻璃的析晶过程及发光性能。结果表明,该微晶玻璃的主晶相为尖晶石(ZnAl2O4),被紫外光激发能够发出红色光;晶化时间的改变导致了尖晶石的逐渐析出,改变了光谱谱线的强度但不改变谱线的位置。Sm3+最佳掺杂摩尔分数为0.4%。     

Conductivity of K_(10)H_3[Dy(SiW_4Mo_7O_(39))_2] Treated by Chemistry-Heated Diffusion of Sm and Gd Permeation

Inthelastfewyears ,theapplicationsofpolyox ometalates (POMs)havereceivedmuchattention[1～ 3]fortheiruniquestructuresandproperties ,however ,thepreparationofthemareallofsolid solidorliquid liquidreactions[1] .Fromtheknowledgeoffundamen taltheory ,wethinkthatrareearthelementscanbepermeatedintoPMOsthroughthesolid gasinterfacereaction ,andtoourknowledgethiskindofexperi menthasnotbeencarriedoutuntilnow .Inthispaper ,thechemistry heateddiffusedperme ationmethod[4 ] wasusedtotreatK10 H3[Dy(SiW4 M…     

Energy transfer and frequency upconversion in Er~（3＋）-Yb~（3＋） codoped oxy-fluoro-tungstosilicate glasses

Er3+-Yb3+ codoped oxy-fluoro-tungstosilicate glasses with infrared-to-visible frequency upconversion luminescence were prepared by melting quenching in air.The effects of Er3+ doping on the optical properties of the samples were measured by means of techniques such as optical absorption spectra and photoluminescence spectra.The results showed that intense green and red signals centered at 546 and 665 nm,corresponding to the 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions of Er3+ by a multiphoton stepwise phonon-assisted excited-state absorption process,respectively,were simultaneously observed by exciting the samples with a diode laser operating at 980 nm at room temperature.The upconversion process was found very sensitive to Er3+ content at a constant Yb2O3 content of 5 mol.%.With the increase of Er3+ content from 0.5% to 1.5%,the upconversion intensity increased gradually.Further increasing of Er3+ content to 3.0% resulted in a significant fluorescence quenching.Moreover,the possible upconversion mechanisms were discussed based on the energy-matching conditions and the quadratic dependence on excitation power.     

Formation and Properties of Phosphate System Protection Glasses Doped by Rare Earth

The forming-regions and properties were studied on phosphate system glasses Sm2O3 doped by two step melting method. It shows that with the increasing of rare earth content, the forming-regions would shrink and the content of Sm2O3 should be controlled in 15 mol %. The structure and absorption spectrum were tested by infra-red spectrum and spectrophotometer. The experimental results provide that with the. increasing of Sm2O3 content, the characteristic absorption peak of 1280 cm- 1 would move to the low wave numbers and vibration weakening, in the absorption spectrum,the intensity of characteristic absorption peak was enhanced and broadened at 1075 nm, and the transmittance of 1060 nm is lessthan 1% .     

Preparation of Sm_2Fe_(17)Alloys in Ca-Sm_2O_3-Fe System

Sm2Fe17alloyisanimportantprecursorforthe preparationofSm2Fe17Nxmagnet.Sincethenitrogen containedSm2Fe17(Sm2Fe17Nx)alloy,asapermanent magnetmaterial,possessesahigherCurietempera ture,largeranisotropyfield,betterresistancetooxi dationandthermalstability,and…     

Bonding of Silicon Nitride Ceramic Composite with RE_2O_3Al_2O_3SiO_2 Glass Solders

Ｓｉｌｉｃｏｎｎｉｔｒｉｄｅｃｅｒａｍｉｃｈａｓａｓｅｒｉｅｓｏｆｅｘｃｅｌｌｅｎｔｐｒｏｐｅｒｔｉｅｓ,ｆｏｒｅｘａｍｐｌｅ,ｈｉｇｈｓｔｒｅｎｇｔｈ,ｈｉｇｈｈａｒｄｎｅｓｓ,ｗｅａｒ,ｃｏｒｒｏｓｉｏｎ,ｏｘｉｄａｔｉｏｎａｎｄｓｈｏｃｋｒｅｓｉｓｔａｎｃｅｅｔｃ．,ａｎｄｉｓａｋｉｎｄｏｆｈｉｇｈｔｅｍｐｅｒａｔｕｒｅｓｔｒｕｃｔｕｒａｌｍａｔｅｒｉａｌｗｉｔｈｅｎｏｒｍｏｕｓｐｏｔｅｎｔｉａｌｉｔｉｅｓｆｏｒｆｕｔｕｒｅｄｅｖｅｌｏｐｍｅｎｔ．Ｂｕｔｈｉｇｈｃｏｓｔｆｏｒ…     

Tailoring effect of Y2O3 on water resistance of Na2O-ZnO-Al2O3-B2O3 glasses

To explore the improving effect of Y₂O₃ on the water resistance of xY₂O₃-(100-x)(0.05 Al₂O₃-0.15 ZnO-0.15 Na₂O-0.65 B₂O₃)(x=0,0.7 mol%,1.4 mol%,2.1 mol%,2.8 mol%) glasses,glass structure and ion migration characteristics were respectively characterized by an infrared spectrometer and an electrochemical workstation.X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive Xray spect...     

Synthesis and Electrical Conductivities of Sm2O3-CeO2 Systems

Solidoxidefuelcell(SOFC)hasattracteda greatattentionasapromisingtechniqueforelectrical powergeneration[1].Thecurrentstate of the art SOFCsusesyttriastabilizedzirconia(YSZ)electro lyte,operatesat800～1000℃duetothelowoxy genionicconductivityoftheYSZelect…     

降低Nd_2O_3中杂质Sm_2O_3的工艺研究

在工业生产实践中，对Ｎｄ－Ｓｍ分组采用大捞大洗和加氨水强化萃取分离的工艺方法实现了一步萃取法除去Ｌａ３＋Ｃｅ３＋Ｐｒ３＋Ｎｄ３＋萃余液中Ｓｍ３＋的目的，经六个月运行，产品Ｎｄ２Ｏ３中杂质Ｓｍ２Ｏ３含量稳定在０．０３％以下。     

Energy transfer from Ce~(3+) to Tb~(3+) and Eu~(3+) in zinc phosphate glasses

Ce3+,Eu3+ and Tb3+ singly doped and Ce3+/Eu3+ and Ce3+/Tb3+ co-doped zinc phosphate glasses were prepared by sintering P2O5,ZnO,Ce2(C2O4)3·10H2O and Eu2O3/Tb4O7 mixtures at 1200 °C in the air for 2 h and then annealing at 450 °C for 10 h.The obtained glasses were homogeneous and transparent.The glasses without Ce3+ were colorless and those with Ce3+ showed slightly yellow.The singly doped glasses showed strong emissions and excitations from doped trivalent rare earth ions.Strong energy transfer from Ce3+ to Tb3+ was observed for Ce3+/Tb3+ coped samples.There were also some very weak evidences for the energy transfer from Ce3+ to Eu3+.     

Effect of Y2O3 and Sm2O3 on Sintering and Mechanical Behaviors of Alumina Ceramics

The effects of Y2O3 and Sm2O3 doping on the sintering temperature, microstructure and mechanical behaviors of Al2O3 ceramics were investigated. The experimental results show that the sintering temperature can be decreased and the mechanical behavior can be improved by adding rare earth in alumina ceramics. The relative density of rare-earthdoped alumina ceramics reaches 98.8% after sintering at 1600 ℃ for 2 h, and its bending strength and fracture toughness reach 439 MPa and 5.28 MPa·m1/2,respectively.Introduction of Y2O3 and Sm2O3 in Al2O3 can restrain the growth of grains, refine the size of grains, and thus form a fine-grained structure. The fracture characteristic is the mixed modes of intergranular and transgranular fracture.     

Y_(2-x)Sm_xW_3O_(12)固溶体的制备及热膨胀性能研究

采用二次固相反应法成功制备出Y2-xSm(xWO4)(3x=0.0,0.2)、(x=1.0,1.4,1.8,2.0)系列固溶体,低掺杂量Y2-xSm(xWO4)(3x=0.0,0.2)为单斜结构(空间群:P2/m),高掺杂量Y2-xSm(xWO4)(3x=1.0,1.4,1.8,2.0)为单斜结构(空间群:C2/c);热重分析表明低Sm掺杂Y2-xSm(xWO4)3具吸水性,且随Sm含量增加而含水量减少,当x≥1.0时,样品完全不吸水;SEM分析了样品的断口形貌与晶粒尺寸;热膨胀性能测试表明,Sm掺杂量(x=0.0,0.2)的Y2-xSm(xWO4)3排除水分子后,具有较强的负热膨胀特性,而掺杂量(x=1.0,1.4,1.8,2.0)的Y2-xSm(xWO4)3具有正膨胀性能。     

Spectroscopic Properties of Er^3＋-Doped TeO2-WO3-ZnO-ZnF2 Glasses

The Er^3 -doped TeO2-WO3-ZnO-ZnF2(TWZOF) glasses were prepared. The absorption spectra, 1.5μm emission spectra and fluorescence lifetimes of Er^3 , excited at 970nm, were measured. The J-O parameters Ωt(t=2, 4, 6), absorption and emission cross-sections were calculated. The dependence of the 1.5μm emission intensity, fluorescence lifetime and bandwidth of the Er^3 emission upon the contents of ZnF2 in glass were investigated. In TWZOF glass, Er^3 ions had a broad emission profile around 1.5μm with the maximum FWHM of 83nm. With the increasing of the content of ZnF2, the emission intensity at peak wavelength and the fluorescence lifetime of Er^3 at 1.5μm increase.     

Study on Modification of Sm2O3 by Ni／Sepiolite Catalyst

A series of Ni-Sm/sepiolite catalysts were prepared by impregnation. The modification of Sm2O3 for Ni/sepiolite was investigated by TPR, XPS and poisoning of CS2, respectively. The results indicate that the addition of Sm2O3 improves the activity of hydrogenation and anti-poisoning ability of Ni/sepiolite catalyst, and it also increases the dispersion of nickel atoms over support and the amount of active nickel atoms in catalyst. Effect of Sm203 on Ni/sepiolite catalyst ineludes not only electronic effect but also steric effect, whereas electronic effect seems to be principal.     

镧热还原氧化钐过程镧的非平衡扩散的研究

运用化学分析法和热重法对镧热还原氧化钐的反应产物镧渣进行分析,得到坩埚不同部位镧渣的镧的扩散量△La和实际反应物料的Sm2O3∶La的比值,并把理论反应物料的Sm2O3∶La和实际的比值相比较。结果表明:真空高温条件下,还原剂金属镧在反应过程中发生了有固定方向的扩散迁移。金属镧从反应物料中的由内向外的非平衡扩散,造成金属镧在反应物料中的分布不均,表面富集而芯部贫乏,降低了还原剂金属镧利用率及产物金属钐收率。     

A white long-lasting phosphor Y2O2S:Tb3+, Sm3+: an improvement of Y2O2S:Tb3+

As an improvement of reported Y202S:Tb3 , a white-light long-lasting phosphor: Y2O2S:Tb3 , Sm3 was prepared by the solid-state reaction. The photo-luminescence spectra showed that the position and shape of Th3 and Sm3 emissions under UV excitation were similar in this host, which ensured a stable white emission color (daylight standard of IEC) under different excitations. The decay curves of co-doped samples indicated that the decay times of emissions of the two ions were close. The thermo-luminescence measurement suggested that the traps created by the doped Sm3 ions were helpful to postpone the white afterglow of co-doped samples. Therefore, thefunction of co-doped Sm3 ions was confirmned as improving the white emission colors of samples and acting as new trap centers.