Gd_(3(1-x))Al_5O_(12)∶RE_(3X)分立材料芯片制备及发光性能研究

将组合材料芯片技术中四元组合法应用于新型发光材料Gd3(1-x)Al5O12∶RE3X的RE激活剂和敏化剂种类优选.由Gd3Al5O12基体材料芯片获得如下的研究结果:1)在紫外激发下(254 nm)Gd3(1-x)Al5O3∶Eu3x材料具有红色荧光性能;2)Pr(n(Pr)∶n(Eu)<1∶10)、Ce(n(Ce)∶n(Eu)<1∶10)共掺杂时会降低发光强度.光谱分析表明:Pr、Ce能级嵌入,使得激活剂和敏化剂发生共振能量传递,是Gd3Al5O12∶Eu(简称为GAG∶Eu)发光效率降低的主要原因.筛选结果得到柠檬酸盐硝酸盐溶胶凝胶法制备粉体筛选实验结果验证.实验结果表明组合法在发光材料开发上具有高效性.     

铝酸钆基体发光薄膜组合芯片制备及其发光性能

组合材料芯片技术是功能材料开发研究的全新方法，能够高效、快速地筛选／优化新材料。采用这一技术快速发现／优化新型铝酸钆系发光材料(Gd1-xAlyOx：Rex)，并通过柠檬酸-硝酸盐燃烧法制备的相同粉体的实验结果，考察了材料芯片筛选结果的可靠性。对发光体在波长为254DE的紫外光激发下进行实验，获得如下的研究结果：铝酸钆基体晶相中n(Gd)：n(A1)的最佳比值为1：1和3：5。GdAlO3中的最佳激活剂(主要是Eu，Pr和Ce)Eu，且Gd1-xAlO3：Eux的主发射峰位置为615nm和593nm。Gd1-xAlO3：Eux中的最佳掺量x值为0．09。     

掺杂RE3+对CaAl2O4:Eu2+,Nd3+发光性能的影响

以燃烧法合成了CaAl2O4∶Eu2+,Nd3+,RE3+紫色长余辉发光材料。实验结果表明,掺杂辅助激活剂Pr3+和Ce3+对CaAl2O4∶Eu2+,Nd3+磷光体发光性能有明显影响。掺杂Pr3+的CaAl2O4∶Eu2+,Nd3+样品的发射峰蓝移;掺杂Ce3+的CaAl2O4∶Eu2+,Nd3+样品的发射峰红移。Pr3+或Ce3+掺杂,可以提高CaAl2O4∶Eu2+,Nd3+磷光体的初始亮度,Pr3+或Ce3+在其中起到增加陷阱密度,提高发光亮度的作用。     

Gd_3Al_5O_(12)∶Eu~(3 )柠檬酸盐硝酸盐燃烧法合成及其发光性能研究

采用柠檬酸盐硝酸盐燃烧法,在较低的温度(900℃)下成功地合成单一晶相Gd3Al5O12∶Eu3 发光粉体,紫外激发荧光光谱分析表明,粉体615 nm和593 nm荧光发射源于Eu3 的5D0-7F2和5D0-7F1跃迁.该方法中各工艺条件(如pH值、柠檬酸/金属离子比、煅烧温度)对Gd3Al5O12∶Eu3 发光性能均有影响,通过试验得出了获得最佳发光性能荧光粉体的工艺参数.     

新型GdAlO3：RE荧光粉多元掺杂及发光机制研究

采用柠檬酸盐硝酸盐燃烧法制备GaAlO3：RE荧光粉体．在紫外光激发T(254m)发现Pr共掺杂对GaAlO3：Eu红色荧光粉体发光有降低作用；Ce共掺杂对GaAlO3：Tb绿色荧光粉体发光有降低作用．激发谱研究表明，共掺杂时分别存在Eu→Pr、Tb→Ce的声子支持的共振能量传递，造成GaAlO3：Eu、GaAlO3：Tb荧光粉体发光强度降低．     

Ca_xSr_(1-x)Al_2O_4∶Eu~(2+)磷光体的制备及性能研究

采用高温固相合成法还原气氛中分别制备了CaxSr( 1-x) Al2 O4∶Eu2 + (x≤ 0 .5 )发光粉 ,其发射光范围为蓝绿色到黄色。合成温度为 1 2 0 0℃ ,激活剂Eu2 + 的最佳摩尔浓度为 0 .6% ,并研究了Sr CO3 与Al2 O3 比值、CaCO3 的添加量对发光材料发光性能的影响。实验中四硼酸钠·十水作为添加剂 ,不仅起到了助熔的作用 ,还提高了磷光体的余辉发光性能。     

CaxSr(1-x)Al2O4:Eu2+磷光体的制备及性能研究

采用高温固相合成法还原气氛中分别制备了CaxSr(1-x)Al2O4:Eu2 (x≤0.5)发光粉,其发射光范围为蓝绿色到黄色.合成温度为1 200℃,激活剂Eu2 的最佳摩尔浓度为0.6%,并研究了SrCO3与Al2O3比值、CaCO3的添加量对发光材料发光性能的影响.实验中四硼酸钠·十水作为添加剂,不仅起到了助熔的作用,还提高了磷光体的余辉发光性能.     

Gd3Al5O12：Eu^3＋柠檬酸盐硝酸盐燃烧法合成及其发光性能研究

采用柠檬酸盐硝酸盐燃烧法，在较低的温度（900℃）下成功地合成单一晶相Gd3Al5O12：Eu^3＋发光粉体，紫外激发荧光光谱分析表明，粉体615m和593m荧光发射源于Eu^3＋的^5D0-^7F2和^5D0-^7F1跃迁．该方法中各工艺条件（如pH值、柠檬酸／金属离子比、煅烧温度）对Gd3Al5O12：Eu^3＋发光性能均有影响，通过试验得出了获得最佳发光性能荧光粉体的工艺参数．     

稀土离子(Gd~(3+),Ce~(3+)/Ce~(4+),Eu~(3+))对Tb~(3+)掺杂硅酸盐玻璃发光性能的影响

研究了(Gd3+,Ce3+/Ce4+,Eu3+)对Tb3+掺杂硅酸盐玻璃发光性能的影响.结果表明:Tb3+掺杂硅酸盐玻璃可以发出弱蓝光(400～460 mm)和较强的绿光(480～600mm).Gd3+对Tb3+的发光起敏化作用,可提高TB3+掺杂硅酸盐玻璃的发光强度.在空气中熔制的玻璃中Ce3+和Ce4+同时存在,Ce3+对Tb3+发光起敏化作用;而Ce4+对Tb3+发光起淬灭作用.由于Ce4+比例比较高,CeO2加入导致TB3+发光强度降低,同时也缩短了Tb3+发光余辉.加入Eu2O3时,Eu3+自身发光分散了激发Tb3+发光的能量,使Tb3+的特征发射强度降低.     

Sr8Si4O12Cl8:Eu3+,M3+(M3+=Bi3+,Gd3+)中Eu3+的敏化发光

以Na2CO3为电荷补偿剂,采用高温固相法合成了碱土氯硅酸盐Sr8Si4O12Cl8:(Eu3 M3 )(M=Bi3 ,Gd3 )荧光材料.X射线衍射分析结果表明:合成的Sr8Si4O12Cl8:(Eu3 ,M3 )为纯四方相.Eu3 的发射主峰位于614 nm,为5D0→7F2的电偶极跃迁,表明Eu3 处于非中心对称格位,即取代Sr2 的位置.通过对其激发光谱和发射光谱研究,发现敏化剂Bi3 ,Gd3 的掺入对Eu3 的发射具有较强的敏化作用,当Bi3 和Gd3 的掺杂量(摩尔分数)分别为5.0%时,Eu3 的相对发光强度分别提高了29.4%和23.6%.     

Ferroelectric Ceramics in the PbMg1/3Nb2/3O3-PbCd1/3Nb2/3O3 System

Solid solutions (1-x)PbMg_1/3Nb_2/3O₃ + xPbCd_1/3Nb_2/3O₃ with x = 0-0.30 are investigated with purpose to work out a capacitor ceramics with good dielectric properties and low sintering temperature. It is found that the perovskite phase forms at sintering near to 980°C and begins to decompose at higher temperatures. When x grows from 0 to 0.30, the Curie temperature linearly grows from -10°C to +25°C, the dielectric permittivity ε_m in the Curie point T_C decreases from 18000 to 6800 and the phase transition becomes more diffused. The dielectric permittivity at room temperature is rather high and the temperature stability is improved. The system is of interest, because it can serve as a base for working out some ceramic materials for capacitors with low sintering temperature, which needs of no special atmosphere at burning.     

3-叠氮甲基-3-甲基氧丁环的合成

以三羟甲基乙烷与碳酸二乙酯为原料,经环化反应合成了3-羟甲基-3-甲基氧丁环(HMM O)。在低温下,HMM O与对甲苯磺酰氯反应生成3-磺酸酯甲基-3-甲基氧丁环(M TM O)。M TM O和叠氮化钠发生叠氮化反应形成叠氮单体3-叠氮甲基-3-甲基氧丁环(AMM O)。三步反应收率分别为76%,96%,85%。用核磁、红外、元素分析和DSC表征了化合物的结构与性能。结构鉴定表明为目标化合物AMM O。     

3-溴甲基-3-甲基氧杂环丁烷的合成

以2,2-二溴甲基丙醇（BBMP）为初始原料,通过与碱发生关环反应生成3-溴甲基-3-甲基氧杂环丁烷（BrMMO）。讨论了碱的种类和用量对BBMP关环产率的影响以及反应体系中碱的浓度、反应温度和反应时间对合成BrMMO产率的影响。通过实验确定的最佳工艺条件为：BBMP与NaOH摩尔比为1.0∶1.1,NaOH醇溶液的质量分数为12%,反应温度为78℃,反应时间为4h时,BrMMO产率为65%。最终产品经元素分析、IR和1HNMR检测确定为BrMMO。该试验工艺简单,原料易得,且溶剂便于回收、污染小。     

Tunable color emission in LaScO3:Bi3+,Tb3+,Eu3+ phosphor

LaScO₃:xBi³⁺,yTb³⁺,zEu³⁺ (x = 0 − 0.04, y = 0 − 0.05, z = 0 − 0.05) phosphors were prepared via high-temperature solid-state reaction. Phase identification and crystal structures of the LaScO₃:xBi³⁺,yTb³⁺,zEu³⁺ phosphors were investigated by X-ray diffraction (XRD). Crystal structure of phosphors was analyzed by Rietveld refinement and transmission electron microscopy (TEM). The luminescent performance of these trichromatic phosphors is investigated by diffuse reflection spectra and photoluminescence. The phenomenon of energy transfer from Bi³⁺ and Tb³⁺ to Eu³⁺ in LaScO₃:xBi³⁺,yTb³⁺,zEu³⁺ phosphors was investigated. By changing the ratio of x, y, and z, trichromatic can be obtained in the LaScO₃ host, including red, green, and blue emission with peak centered at 613, 544, and 428 nm, respectively. Therefore, two kinds of white light-emitting phosphors were obtained, LaScO₃:0.02Bi³⁺,0.05Tb³⁺,zEu³⁺ and LaScO₃:0.02Bi³⁺,0.03Eu³⁺,yTb³⁺. The energy transfer was characterized by decay times of the LaScO₃:xBi³⁺, yTb³⁺, zEu³⁺ phosphors. Moreover absolute internal QY and CIE chromatic coordinates are shown. The potential optical thermometry application of LaScO₃:Bi³⁺,Eu³⁺ was based on the temperature sensitivity of the fluorescence intensity ratio (FIR). The maximum S_a and S_r are 0.118 K⁻¹ (at 473.15 K) and 0.795% K⁻¹ (at 448.15 K), respectively. Hence, the LaScO₃:Bi³⁺,Eu³⁺ phosphor is a good material for optical temperature sensing.     

2,2,3-三氯-3-苯基-3-(3-甲基苯甲酰基)丙腈的合成研究

以苯甲酰氯、四氯化碳、间甲基苯甲酰氰为原料,合成了标题化合物。重点考察了氰化过程中不同原料配比、反应温度、时间、溶剂和催化剂用量对收率的影响。实验结果表明,其最佳反应条件为:n(1,1,2-三氯-2-苯基乙烯)∶n(3-甲基苯甲酰氰)=1∶1.2,二氯甲烷为反应溶剂,3 mmol催化剂三乙胺,室温反应5 h,总收率达80.6%。     

3-溴甲基-3-甲基氧杂环丁烷的合成

以2,2-二溴甲基丙醇(BBMP)为初始原料,通过与碱发生关环反应生成3-溴甲基-3-甲基氧杂环丁烷(BrMMO).讨论了碱的种类和用量对BBMP关环产率的影响以及反应体系中碱的浓度、反应温度和反应时间对合成BrMMO产率的影响.通过实验确定的最佳工艺条件为:BBMP与NaOH摩尔比为1.0∶1.1,NaOH醇溶液的质量分数为12%,反应温度为78℃,反应时间为4 h时,BrMMO产率为65%.最终产品经元素分析、IR和1HNMR检测确定为BrMMO.该试验工艺简单,原料易得,且溶剂便于回收、污染小.     

The Preparation and Crystal Structure of TlMnCl3, TlFeCl3, TlCoCl3 and TlNiCl3

The compounds TlMnCl₃, TlFeCl₃, TlCoCl₃ and TlNiCl₃ were prepared by heating T1C1 with the corresponding transition metal dichloride in an evacuated ampoule. Atomic positions were determined from powder photographs. All four compounds were found to be related to the perovskite type structure. TlMnCl₃ has a cubic structure, space group Pm3m, with a_o = 5.025 Å. The other three compounds are hexagonal, probable space group P6₃mc, with cell dimensions (in Å) a₀ = 6.976 and c₀ = 6.008 for the Fe compound, a₀ = 6.907 and c₀ = 5.981 for the Co compound and a₀ = 6.863 and c₀ = 5.881 for the Ni compound. The three hexagonal compounds are isomorphous. A measureable concentration of basal plane stacking faults was found to occur in TlFeCl₃ and also, to a lesser degree, in TlCoCl_3.     

Ba3Tb(BO3)3:Eu3+的制备与发光性质

采用高温固相法合成了Ba3Tb(BO3)3:Eu3+红色荧光粉,并研究了Ba3Tb(BO3)3:Eu3+的发光特性。Ba3Tb(BO3)3:Eu3+的激发光谱包含250nm～330nm和350nm～400nm的2个宽带,最大峰值位于383nm,可以被紫外-近紫外发光二极管(light-emitting diodes,LED)有效激发。Ba3Tb(BO3)3:Eu3+的发射谱显示出4组发射峰,其主发射峰位于620nm,对应Eu3+的5D0→7F2跃迁;Eu3+掺杂摩尔分数为2%时,Ba3Tb(BO3)3:Eu3+发光亮度最高。经分析发现Ba3Tb(BO3)3:Eu3+存在Tb3+→Eu3+的能量传递。     

Thermal analyses of poly(3-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate), and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)

Thermal analyses of poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(HB–HV)], and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(HB–HHx)] were made with thermogravimetry and differential scanning calorimetry (DSC). In the thermal degradation of PHB, the onset of weight loss occurred at the temperature (°C) given by T_o = 0.75B + 311, where B represents the heating rate (°C/min). The temperature at which the weight-loss rate was at a maximum was T_p = 0.91B + 320, and the temperature at which degradation was completed was T_f = 1.00B + 325. In the thermal degradation of P(HB–HV) (70:30), T_o = 0.96B + 308, T_p = 0.99B + 320, and T_f = 1.09B + 325. In the thermal degradation of P(HB–HHx) (85:15), T_o = 1.11B + 305, T_p = 1.10B + 319, and T_f = 1.16B + 325. The derivative thermogravimetry curves of PHB, P(HB–HV), and P(HB–HHx) confirmed only one weight-loss step change. The incorporation of 30 mol % 3-hydroxyvalerate (HV) and 15 mol % 3-hydroxyhexanoate (HHx) components into the polyester increased the various thermal temperatures T_o, T_p, and T_f relative to those of PHB by 3–12°C (measured at B = 40°C/min). DSC measurements showed that the incorporation of HV and HHx decreased the melting temperature relative to that of PHB by 70°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 90–98, 2001