Preparation of Sr2CeO4:Eu3+,Dy3+ white luminescence phosphor particles and thin films by using an emulsion liquid membrane system

Sr(2)CeO(4) and Sr(2)CeO(4):Eu(3+),Dy(3+) phosphor particles and thin films were prepared by using an emulsion liquid membrane (ELM, water-in-oil-in-water (W/O/W) emulsion) system, containing VA-10 (2-methyl-2-ethylheptanoic acid) as extractant (cation carrier). A two-step extraction enabled efficient extraction for Sr(3+) and rare earth ions, and the resulting precursor metal oxalate particles produced in the internal water phase of the ELM system were about 60 nm in diameter. Calcination of the oxalate particles in air gave submicrometer-sized Sr(2)CeO(4) and Sr(2)CeO(4):Eu(3+),Dy(3+) particles, which showed blue and white luminescence, respectively, by UV excitation. Blue and white luminescence phosphor thin films were also prepared by soaking alumina substrates into the W/O emulsion containing precursor oxalate particles, followed by calcination in air.     

Preparation of Gd2O3:Yb,Er and Gd2O2S:Yb,Er infrared-to-visible conversion phosphor ultrafine particles using an emulsion liquid membrane system

Upconverting phosphor fine particles (Gd2O3:Yb,Er and Gd2O2S:Yb,Er) have been prepared, using an emulsion liquid membrane (ELM, water-in-oil-in-water (W/O/W) emulsion) system. The composite Gd-Yb-Er oxalate particles obtained in the ELM system were mainly 20-60 nm in size, together with a smaller amount of submicrometer-sized spherical particles. Nanometer-sized Gd2O3:Yb,Er and Gd2O2S:Yb,Er particles were obtained by calcination in air and in sulfur atmosphere, respectively, of the precursor oxalate particles prepared in the ELM system. Upconversion emissions (red and green) were obtained from the Gd2O3:Yb,Er and Gd2O2S:Yb,Er particles prepared in the ELM system under infrared excitation (lambdaex=980 nm) via a two-photon process. Upconversion phosphor fine particles, about 50 nm in diameter, may be applied to the luminescent reporter material for the detection of the targeted analyte in immunoassays or DNA assays.     

Preparation of Gd(2)O(3) : Eu(3+) and Gd(2)O(2)S : Eu(3+) phosphor fine particles using an emulsion liquid membrane system

Size- (submicrometer-sized) and morphology- (spherical) controlled composite Gd-Eu oxalate particles were prepared in an emulsion liquid membrane (water-in-oil-in-water emulsion) system. The oxalate particles thus prepared were calcined in air to obtain Gd(2)O(3) : Eu(3+) phosphor particles and in sulfur atmosphere to obtain Gd(2)O(2)S : Eu(3+) phosphor particles. These submicrometer-sized spherical phosphor particles showed photoluminescence properties with emission peak at 614 nm for Gd(2)O(3) : Eu(3+) and 628 nm for Gd(2)O(2)S : Eu(3+).     

Preparation of yttrium oxysulfide phosphor nanoparticles with infrared-to-green and -blue upconversion emission using an emulsion liquid membrane system

Yttrium oxysulfide upconverting phosphor nanoparticles, doped with Yb as a sensitizer and Er (or Ho, Tm) as an activator, have been prepared via a solid-gas reaction using precursor oxalate particles obtained in an emulsion liquid membrane (ELM, water-in-oil-in-water (W/O/W) emulsion) system. The resulting Y(2)O(2)S:Yb,Er particles, mainly smaller than 50 nm in diameter, demonstrated green upconversion emission under infrared excitation (lambdaex = 980 nm) via a two-photon process. Distinct green and blue upconversion emission were also demonstrated under the same infrared excitation from Y(2)O(2)S:Yb,Ho and Y(2)O(2)S:Yb,Tm nanoparticles, respectively. These upconverting phosphor nanoparticles, together with Y(2)O(3):Yb,Er infrared-to-red upconverting phosphor particles, with different emission under the same infrared excitation may be applied to the luminescent reporter materials for the detection of the targeted analyte in multiplexed assays.     

Redox-driven transport of copper ions in an emulsion liquid membrane system

A new redox-driven type of emulsion liquid membrane separation is described. Milligram amounts of copper(II) in 0.2 M hydrochloric acid were reduced to copper(I) in the presence of ascorbic acid (1 M≡1 mol l⁻¹). The copper solution was emulsified with a (1+4) mixture of toluene and n-heptane using Span-80 (sorbitan monooleate) as an emusifier. The resulting water-in-oil emulsion was dispersed in 0.2 M hydrochloric acid containing hydrogen peroxide and neocuproine (2,9-dimethyl-1,10-phenanthroline) by stirring for 10 min. The copper in the internal aqueous phase was selectively transported to the external one, leaving other heavy metals (e.g., Mn, Co, Ni, Cd and Pb) in the internal aqueous phase. After collecting the dispersed emulsion globules, they were demulsified by heating and the metals in the segregated aqueous phase were determined by graphite-furnace atomic absorption spectrometry (GFAAS). The selective transport of copper offered the multielement separation of trace heavy metals from a copper matrix, allowing the GFAAS determination of impurities at the 0.01% level in copper metal.     

乳状液膜法分离水中的铬

乳状液膜法由于其独特的物理化学性质,已广泛用于金属离子的萃取分离[1～3]。本文以span80-煤油-NaOH液膜体系分离水中铬。不加流动载体,利用内、外相中被分离物的浓度梯度实现物质迁移。当Cr2O2-7进入内相时,与内相的NaOH发生反应,在内相高浓度的NaOH存在下,可保持Cr2O2-7在液膜两侧有最大的浓度梯度,促使Cr2O2-7的迁移,实现Cr2O2-7与外相溶液的分离。1　实验部分1 1　仪器与试剂D40-1型电动搅拌器(杭州仪表电机厂),78-1型磁力加热搅拌器(江苏金坛新一佳仪器厂),721型分光光度计(上海第三分析仪器厂)。铬标准溶液(100ml/L):准…     

Y2O3和Nd2O3介孔薄膜的制备与表征

以聚乙烯合丁烯-嵌-聚氧乙烯嵌段共聚物(PHB-PEO)作模板, 采用蒸发诱导自组装方法, 分别制备了Y2O3和Nd2O3介孔薄膜. 用小角、广角X射线衍射和透射电子显微镜对薄膜样品在不同的热处理阶段进行了表征. 结果表明, 所制备的Y2O3和Nd2O3薄膜样品呈现一种大孔径(平均孔径分别约为11.5和12.5 nm)、有序的立方扭曲球形孔排列、稳定于450 ℃并具有部分晶态孔壁结构的介孔薄膜材料.     

纳米级均分散氧化钇粉末的制备

运用素分解法及“交替淬冷－快热”技术，成功地制备了经钇的纳米级均分散胶体粒，运用ＴＥＭ对产物分析后发现颗粒分散性好，分布窄，呈规则球形。最小粒径为６５ｎｍ。并对产物进行纯度分析，确定了杂质元素及含量。详细讨论了“交替淬冷－快热”技术运用于配方的基本原理。     

铜在乳状液膜体系中的迁移行为

近年来膜分离技术在环境治理方面得到广泛应用。本文研究了铜在span80-TBP（磷酸三丁酯）-煤油-NH3液膜分离体系中的迁移行为。用TBP作为载体,在溶液中迁移时,在外相与膜相界面上形成中性络合物后穿过膜相,在膜相与内相界面上络合物再与NH3反应,生成铜氨络离子,释放出来的TBP又返回膜相。     

Separation study of cadmium through an emulsion liquid membrane

A study of the transport of Cd(2+) ions through a tri-ndashoctylamine(TOA)-sorbital monooleate (Span 80)-oxylene liquid membrane has been performed with varying concentrations of HCl, KI, TOA, Span 80 and NaOH in the feed, membrane and stripping solutions. Maximum transport was observed at 0.01 M KI, 0.025 M HCl, 0.015 M TOA, 3% (w/v) Span 80 and 0.025 M NaOH. With this system, cadmium could be completely separated from Zn(2+), Fe(2+), Co(2+), Ni(2+), Cr(3+) and Mn(2+). The transport mechanism of this metal ions through the membrane has been discussed.     

Eu3+掺杂Y2O3-Al2O3-SiO2玻璃的制备与荧光性能研究

采用高温熔融法制备了Eu³⁺掺杂Y₂O₃-Al₂O₃-SiO₂荧光玻璃,探讨了成分对该体系玻璃形成能力的影响,并对不同Eu³⁺掺杂浓度下的荧光性能进行了研究.结果表明,熔融温度为1500℃条件下,SiO₂含量对该体系的玻璃形成能力影响明显,Y/Al摩尔比为3/5时,SiO₂含量在52%-68%(摩尔分数)范围内时可以获得玻璃.掺杂Eu³⁺的Y₂O₃-Al₂O₃-SiO₂玻璃具有荧光性能,在395nm波长激发下,在588 nm和614 nm处出现明显的发射峰.随着Eu³⁺掺杂浓度的增加,该荧光玻璃的发射波长不变,但发射强度有所变化;当Eu³⁺掺杂浓度为1.5%(摩尔分数)时,特征发射峰强度最大.     

Separation study of mercury through an emulsion liquid membrane

A study of the transport of Hg(II) ions through a tri-n-octylamine (TOA) - sorbital monooleate (Span 80) -toluene liquid membrane has been performed with varying concentrations of HCl, KCl, TOA, Span 80 and NaOH in the feed, membrane and stripping solutions. Maximum transport was observed with 0.01 M KCl, 2.5 x 10(-2) M HCl, 1.5 x 10(-2) M TOA, 3% (w/v) Span 80 and 0.05 M NaOH. With this system, mercury could be completely separated from Cu, Zn, Fe, Co, Ni, Pb, Mn and Cd. The transport mechanism of this metal ion through the membrane is based on the association of metal anions (HgCl(4)(2)) with protonated TOA molecules at the feedside interface, diffusion through the membrane, decomposition of the complex at the strip-solution-side membrane interface under alkaline conditions, and backdiffusion of TOA molecules. Transport with the membrane is dependent on the concentration gradient but in the surrounding solutions it is inversely related to the concentration gradient.     

Separation study of cadmium through an emulsion liquid membrane using triisooctylamine as mobile carrier

A study of the transport of Cd(2+) ions through a triisooctylamine (TIOA)-sorbitan monooleate (Span 80)-dimethylbenzene liquid membrane has been performed with varying concentrations of HCl, KI, TIOA, Span 80 and NaOH in the feed, membrane and stripping solutions. Maximum transport was observed with 0.025 M HCl, 0.01 M KI, 0.02 M TIOA, 3% (w/v) Span 80 and 0.05 M NaOH. With this system cadmium could be completely separated with Cu(2+), Zn(2+), Fe(2+), Co(2+), Ni(2+), Mn(2+), Cr(3+) and Al(3+). The transport mechanism of this metal ions through the membrane has been discussed.     

Molecular dynamics simulations of La2O3 thin films on SiO2

Classical molecular dynamics is used to investigate the equilibrium state of the surface region and interface of heteroepitaxial La2O3 thin films.Due to the lattice mismatch,heteroepitaxial thin films are subject to very large stress.For this reason the behavior of La2O3 thin films at SiO2interface becomes an important concern.Our result indicates that La2O3 can uniformly wet SiO2 surface.The properties of the simulated films are analyzed and the lack of any discernible crystalline phase in epitaxial La2O3 on SiO2 indicates that the lattice mismatch between SiO2 and La2O3 is sufficiently large to prevent the formation of even short-range orders in La2O3 film.     

The system Y2O3−CaO−P2O5

The ternary system Y₂O₃?CaO?P₂O₅ has been examined by DTA, X-ray diffraction, IR and microscopic methods. Its phase diagram has been provided within the composition range YPO₄?Ca₃(PO₄)₂?P₂O₅. The occurrence of four mixed phosphates: Ca₃Y(PO₄)₃, CaYP₃O₁₀, CaY(PO₃)₅, Ca₂Y(PO₃)₇ has been discovered in the system. Basic X-ray data have been determined for these newly discovered compounds and several methods of their synthesis developed.     

The system Y2O3−MgO−P2O5

The previously unknown ternary system Y₂O₃?MgO?P₂O₅ has been examined by thermal, X-ray and microscopic methods. Its phase diagram has been determined over the composition range: YPO₄?Mg₃(PO₄)₂?Mg(PO₃)₂?Y(PO₃)₃. In the system, the existence of two mixed phosphates: MgYP₃O₁₀ and MgY(PO₃)₅ has been found, and they occur, according to their composition, at the sections YPO₄?Mg(PO₃)₂ and Y(PO₃)₃?Mg(PO₃)₂, respectively.     

无机溶胶凝胶法制取Y2O3纳米微粒

以廉价无机盐为原料，采用溶胶凝胶法制备出尺度均匀，一次颗粒尺寸平均为60nm，颗粒呈球形的高纯Y2O3，纳米微粒。研究发现适量SO4^2-离子的添加对生成前驱物溶胶及煅烧得到球形的Y2O3纳米微粒起关键作用。对前驱物在煅烧过程中的物相变化进行了研究，分析了煅烧温度对产物粒度和纯度的影响，结果表明在不使生成物颗粒过分长大的前提下，升高煅烧温度有助于制取高纯和晶化完全的Y2O3微粉。     

静电纺丝法制备Y2O3纳米纤维与表征

采用静电纺丝法制备了PVA/Y(NO3)3复合纳米纤维,在适当的温度下进行热处理,得到Y2O3纳米纤维. 利用XRD,SEM,TG-DTA,FTIR等现代分析手段对样品进行了表征. XRD分析表明,PVA/Y(NO3)3复合纤维为无定型,焙烧温度在600 ℃以上得到晶态单相的Y2O3纳米纤维,属于立方晶系,空间群为Ia3. SEM分析表明,PVA/Y(NO3)3复合纤维表面光滑,平均直径为110 nm. 焙烧温度对Y2O3纳米纤维的形成有重要影响. 600 ℃焙烧得到的Y2O3纳米纤维的平均直径约50 nm,900 ℃焙烧得到的Y2O3纳米纤维由纳米颗粒堆积而成,部分已断裂. TG-DTA和FTIR分析表明,PVA,Y(NO3)3以及水分在600 ℃以上时完全分解挥发,最终样品为晶态单相的Y2O3纳米纤维.     

Investigation of opto-dielectric properties of Ti-doped Ga2O3 thin films

Several Ti-incorporated Ga-oxide (Ga₂O₃) thin films with different amounts of Ti contents have been prepared by vacuum evaporation method on glass and silicon substrates. The Ti incorporation level was measured with energy dispersion X-ray spectroscopy (EDX) method. The crystalline structure of the prepared films was determined with X-ray diffraction method. Experimental data indicate that Ti⁴⁺ ions doped in host Ga₂O₃ form solid solutions (SS) even with so large Ti% content ∼10.4% wt. All the prepared solid solutions have the known orthorhombic (ɛ-phase) phase of Ga₂O₃. The doping controls the optical and electrical properties of the host Ga₂O₃. It was found that the bandgap of the prepared undoped Ga oxide is 5.23 eV, which was decreased monotonically with increasing of Ti doping level so that it is possible to engineer the bandgap. Furthermore, the electrical measurements show that with Ti doping, it is possible to turn the high-k Ga oxide into low-k dielectric material. The optical sensitivity of the capacitance, dissipation factor, and ac-conductance of the Ga₂O₃:Ti films grown on Si was studied as a function of Ti-doping level. It was observed that the prepared Ga₂O₃:Ti film with 6–10% doping level has the highest photosensitivity among the other samples.