Yb~(3+)/Ho~(3+)共掺Ge_(25)Ga_5S_(70)玻璃中红外发光特性

用熔融急冷法制备了系列Yb3+/Ho3+共掺Ge25Ga5S70硫系玻璃,测试了样品的吸收光谱以及980nm激光泵浦下中红外荧光光谱特性,用Judd–Ofelt理论计算分析了单掺Ho3+在Ge25Ga5S70玻璃中的强度参数Ωi(i=2,4,6)、自发辐射跃迁几率、荧光分支比和辐射寿命等光谱参数。研究了Yb3+/Ho3+共掺样品在980nm激光泵浦下获得的Ho3+:2.9μm中红外荧光光谱性质,表明Yb3+/Ho3+之间存在能量共振转移。当固定Yb3+掺杂浓度为0.5%(质量分数,下同),随着Ho3+掺杂浓度从0增加为0.7%,Yb3+:2F5/2能级寿命明显单调下降,说明Yb3+/Ho3+之间有效的能量传递主要来源于Yb3+:2F5/2能级向Ho3+:5I6能级的共振能量传递。运用Futchbauer-Ladenburg公式计算比较了不同掺杂浓度下Ho3+:5I6→5I7跃迁的受激发射截面。     

Tm3+-Yb3+双掺Li2O-B2O3-SiO2系透明玻璃陶瓷的制备及表征

本文制备了以Li2SiO3为主晶相Li2O-B2O3-SiO2系透明玻璃陶瓷,并研究了B2O3的含量对于玻璃陶瓷结构的影响.利用DSC、XRD和SEM等测试手段进行了表征.以Tm3+/Yb3+共掺作为上转换研究对象,研究了该系玻璃陶瓷的光谱性质.在980 nm激光激发下,Tm3+/Yb3共掺的LBS系玻璃陶瓷中观察到强的474 nm的蓝色、650nm的红色上转换发光,并确定蓝红光均为三光子过程.研究了上转换发光与Tm3+/Yb3+质量比的关系.     

敏化剂离子对Tm~(3+)掺杂的镓锗玻璃1.47-μm发光特性研究

报道了Tm3+掺杂的15Ga2O3-75Ge O2-10Na2O玻璃1.47-μm发光,应用Judd-Ofelt理论计算了玻璃的强度参数t(t=2,4,6)、自发辐射几率A、荧光分之比β等各项光谱参数以及峰值发射截面σepeak。通过测量光谱性能研究了敏化剂离子(Ho3+,Tb3+,Sm3+,Dy3+)掺杂浓度对Tm3+离子1.47-μm波段发光性能的影响,分析了Tm3+和这些敏化剂离子之间的能量传递过程。研究表明镓锗钠玻璃是适用于S波段光纤放大器的一种潜在基质材料,而掺杂一定浓度的敏化剂离子迅速降低了Tm3+:3F4能级的粒子数,而对3H4能级粒子数影响不大,极大地提高了Tm3+离子在1.47-μm波段的发光效率,且Tb3+是最有效的敏化剂离子。     

Tm3+掺杂Ge-Ga-Se-CsI玻璃中红外发光和增益特性研究

用熔融急冷法制备了系列Tm3+掺杂浓度的Ge-Ga-Se-CsI硫卤玻璃样品,通过测试的吸收光谱和Judd-Ofelt 理论计算了Tm3+离子的强度参数(Ωi,i=2,4,6)、自发辐射跃迁几率(A)、荧光分支比(β)、以及辐射寿命(Trad)等光谱参数.研究了800 nm激光泵浦下样品红外荧光特性与掺杂浓度之间的关系,计算了常温下Tm3+:3 F4→3 H6(1.8 μm)和3H5→3F4(3.8μm)发射截面以及3F4→3H6(1.8 μm)跃迁的增益截面与波长的函数关系.     

Tm~(3+)/Ho~(3+)/Yb~(3+)掺杂钠铝碲酸盐陶瓷上转换荧光分析

采用高温固相熔融法制备Tm3+/Yb3+、Ho3+/Yb3+和Tm3+/Ho3+/Yb3+掺杂钠铝碲酸盐陶瓷。用X射线衍射分析钠铝碲酸盐陶瓷的结构,结合974nm激光激发的上转换荧光,探讨上转换荧光强度与激发功率的关系。根据计算Tm3+/Ho3+/Yb3+掺杂样品上转换荧光色坐标,研究荧光色坐标与激发功率的关系。结果表明:钠铝碲酸盐陶瓷整体上呈无序结构,但存在少量α-Al2O3。由于Tm3+的上转换蓝光发射属三光子过程,Tm3+/Ho3+/Yb3+掺杂体系中,蓝光发光强度随激发功率增加而迅速增长的趋势比绿光和红光的更为明显。随着激发功率的增大,色坐标在1931CIE色品图中沿左下方朝蓝绿区方向移动,实现了上转换荧光的色彩变换。     

Yb3+和Ce3+对Er3+掺杂碲酸盐玻璃光谱性质的影响

;在掺Er3 的70TeO2-20ZnO-5La2O3-5Nb2O5(各组成以摩尔比计)玻璃中引入Yb3 和Ce3 ,分析比较了975nm泵浦下Yb3 和Ce3 对于Er3 的1.5μm波段红外荧光和可见上转换发光特性的影响.结果表明:在掺Er3 的碲酸盐玻璃中引入Yb3 ,有效地提高了Er3 的1.5μm波段红外荧光强度、展宽了其荧光谱,也显著增强了可见上转换发光强度.随着玻璃中Ce3 的引入,进一步提高了Er3 的4I11/2→4I13/2能级间无辐射弛豫速率,1.5μm波段红外荧光也得到进一步增强,但可见上转换发光大幅减弱.与Er3 /Yb3 共掺相比,Er3 /yb3 /Ce3 共掺碲酸盐玻璃是一种更为理想的应用于1.5 μm波段宽带放大器的增益介质.     

Spectroscopic Properties and Energy Transfer Mechanism of Er^3＋/Yb^3＋/Ce^3＋ Codoped Tellurite-based Glasses

为进一步揭示多稀土离子共掺低声子能量玻璃中Er3＋的光谱特性及其发光机理,采用高温熔融法制备了Er3＋/Yb3＋/Ce3＋共掺组分为（72.5–x）TeO2–20ZnO–5La2O3–0.5Er2O3–2Yb2O3–xCe2O3（x=0,0.4,0.7,1.0,摩尔分数x%）的碲酸盐玻璃,通过测量吸收光谱、荧光光谱和无掺杂样品的Raman光谱,以及计算相应能级间的吸收截面和受激发射截面,研究并分析了Yb3＋和Ce3＋离子掺杂对于Er3＋的1.55μm波段荧光特性的影响。结果显示：Yb3＋和Ce3＋的引入能显著增强975nm泵浦下Er3＋的1.55μm波段荧光强度。分析表明：Er3＋在1.55μm波段荧光强度的增强主要归结于Yb3＋/Yb3＋、Yb3＋/Er3＋离子间的共振能量传递过程以及基于单声子和双声子辅助的Er3＋/Ce3＋离子间的能量传递过程,并通过计算得到了相应稀土离子间的能量传递微观参数和声子所作的贡献比。     

Tm3+掺杂玻璃光纤研究进展

2 μm波段光纤激光可被广泛应用于激光雷达、生物医疗、环境监测以及光谱学等领域,而Tm³⁺掺杂玻璃光纤是2 μm波段光纤激光重要的增益介质。本文从Tm³⁺掺杂玻璃的发光特性出发,介绍了Tm³⁺掺杂玻璃光纤的制备技术,综述了不同玻璃基质材料掺Tm³⁺光纤的研究进展。最后,指出了制备高性能Tm³⁺掺杂玻璃光纤需要解决的关键问题,提出了可能的解决方法,并对Tm³⁺掺杂玻璃光纤发展趋势进行了展望。     

Tm3+/Ho3+共掺碲酸盐玻璃中Tm3+交叉弛豫主导的2.0μm发光特性

研究了不同摩尔分数Tm3 掺杂下Tm3 /Ho3 共掺碲酸盐玻璃在2.0μm处的发光特性.此发光包括两个过程:Tm3 之间的交叉弛豫过程;通过Tm3 与Ho3 之间的能量转移,将能量传递给Ho3 而使Ho3 跃迁至5I7能级上产生布居,当Ho3 跃迁回基态时则发出波长为2.0μm的光.计算了Tm3 的交叉弛豫速率,并根据速率方程分析了Tm3 的交叉弛豫机理.结果表明:随着Tm3 浓度增加,交叉弛豫逐渐增强;2.0μm处发光的强度逐渐增强.证明了在Tm3 /Ho3 共掺情况下,2.0μm处的发光强度取决于Tm3 的交叉弛豫强度.     

Ho~(3+)/Yb~(3+)共掺TeO_2-ZnO-ZnX_2(X=F,Cl,Br)玻璃的结构和红外发光特性(英文)

采用熔融法制备TeO2-ZnO-ZnX2(X=F,Cl,Br)系统氧卤玻璃块体,并测定了玻璃的各项特征温度。通过Raman光谱和X射线光电子能谱分析了卤化物的引入对玻璃网络结构稳定性的影响。结果表明,加入ZnF2比加入ZnCl2或ZnBr2对Ho3+/Yb3+共掺的碲酸盐玻璃的近红外荧光输出有更明显的效果和规律性。与加入ZnCl2和ZnBr2相比,加入ZnF2对Ho3+/Yb3+共掺的碲酸盐玻璃近中红外的荧光输出影响更加明显和规律。ZnF2虽会抑制1μm处发光但能增强1.2和2μm的发光,同时2μm处荧光输出的量子效率也得到大幅提升。比起使用ZnBr2,使用ZnF2和ZnCl2替代ZnO能更好地提高玻璃的光学性能和热稳定性。在这3种卤化锌中,氟化锌对稀土发光的增强起着更为重要的作用。     

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